CriticalCVE-2023-44487

    IBM Planning Analytics: Mehrere Schwachstellen

    Published In CISA KEV since Sources: BSI

    What is affected, what to do

    A flaw was found in handling multiplexed streams in the HTTP/2 protocol. A client can repeatedly make a request for a new multiplex stream and immediately send an RST_STREAM frame to cancel it.

    The vulnerability is being actively exploited; treat it as a priority. The available sources name no fixed version. Check the vendor guidance in the references below. Immediate actions, mitigation and detection rules are in the runbook below.

    Conflicting version data — version display is hidden until the data is resolved.

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.5

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: BSI

    —

    EPSS score

    No value is available for this vulnerability.

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    159.56 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    actively exploitedSource: CSA/SingCERT How we classify
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    7.5 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    7.5
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    Actively exploited
    Published
    In CISA KEV since

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This flaw sits in the HTTP/2 protocol itself, so it cuts across vendors. It is network-reachable without authentication or user interaction and affects availability only, not confidentiality or integrity. Attackers use it to launch Layer 7 DDoS floods with relatively small botnets against public web services, APIs and portals; it ranks among the CVEs most likely to be exploited, and CISA reports no known ransomware use. For KRITIS and NIS2 entities running public citizen, customer or operational portals, treat it as high priority, since availability is a protection goal and significant outages trigger reporting obligations. Purely internal HTTP/2 services behind a patched edge can follow in a later patch cycle.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Inventory every internet-facing endpoint with HTTP/2 enabled (reverse proxies, load balancers, API gateways, application servers): curl -sI --http2 https://<host> or nmap --script ssl-enum-ciphers -p 443 (check for ALPN h2). You cannot prioritise without this list.
      • Upgrade Apache Tomcat: versions 9.0.0 through 9.0.80 and 11.0.0 (milestone builds) are affected. Move to a release later than 9.0.80, or to the fixed 11.0.x build listed in the Apache security advisory.
      • Bring the other listed components to their fixed versions: Akka HTTP Server 10.5.3, Amazon OpenSearch Data Prepper 2.5.0, Apache APISIX 3.6.1, Apache Solr 9.4.0.
      • For every other HTTP/2 stack (web servers, proxies, CDN, ingress controllers, runtime libraries), a patch is available from the vendor — look up the fixed version in the vendor advisory. Patch edge components before internal backends.
      • Where patching isn't immediately possible, temporarily disable HTTP/2 at the edge and fall back to HTTP/1.1 (e.g. in Tomcat, remove <UpgradeProtocol className="org.apache.coyote.http2.Http2Protocol"/> from the connector). Accept the performance hit.
      • Contact your DDoS mitigation provider or CDN and get written confirmation that Rapid Reset protection is active on their side. Record the emergency contact in the incident runbook.

    2. Runbook step 2

      Mitigation layers

      • Network/edge: Terminate HTTP/2 only on a hardened, patched layer (CDN, WAF, patched reverse proxy). Have backends speak HTTP/1.1 internally so that unpatched app servers are never directly exposed.
      • Protocol configuration: Cap concurrent streams per connection (Tomcat Http2Protocol attribute maxConcurrentStreams, or the equivalent directives in your proxy). Where the implementation supports it, close connections with excessive stream cancellations (RST_STREAM) via GOAWAY.
      • Rate limiting: Apply per-source-IP limits on both new TCP/TLS connections and requests per second, and bound connection lifetime and requests per connection.
      • IPS (TLS-terminated): Use a Suricata threshold on RST_STREAM frames, e.g. alert http2 any any -> $HOME_NET any (msg:"CVE-2023-44487 HTTP/2 Rapid Reset"; http2.frametype:RST_STREAM; threshold:type both,track by_src,count 500,seconds 10; sid:9244871; rev:1;). This only works where TLS is decrypted.
      • Capacity/resilience: Review autoscaling ceilings and cost alerts, because an attack can otherwise drive runaway resource consumption and spend. Make sure upstream scrubbing is covered contractually with your provider.

    3. Runbook step 3

      Detection rules

      • Proxy/web-server logs: A surge in cancelled requests is the main signal (nginx status 499, Envoy response flag DC, Tomcat access-log entries with 0 bytes and near-zero duration). SPL: index=web status=499 | bin _time span=1m | stats count by _time, clientip | where count>1000
      • Load balancer/CDN telemetry: Watch for a sharply rising request-to-connection ratio from a small set of source IPs, and for "client reset" or "stream reset" counters in provider dashboards or cloud LB logs.
      • Suricata/Zeek: Look for high per-source rates of http2.frametype:RST_STREAM, Suricata HTTP/2 app-layer anomaly events, and Zeek conn.log entries showing long-lived 443 sessions with very high orig_pkts but small response sizes.
      • Host metrics: Alert on CPU saturation or thread-pool exhaustion on the app server without a matching rise in successful (2xx) responses. Correlate "CPU > 90 % and 2xx rate dropping" as a single alert.
      • Sigma shape: logsource: category: webserver / detection: selection: sc-status: 499 / condition: selection | count() by c-ip > 1000 within a 1-minute timeframe.

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    A flaw was found in handling multiplexed streams in the HTTP/2 protocol. A client can repeatedly make a request for a new multiplex stream and immediately send an RST_STREAM frame to cancel it. This creates extra work for the server setting up and tearing down the streams while not hitting any server-side limit for the maximum number of active streams per connection, resulting in a denial of service due to server resource consumption. Red Hat has rated the severity of this flaw as 'Important' as the US Cybersecurity and Infrastructure Security Agency (CISA) declared this vulnerability an active exploit. CVE-2023-39325 was assigned for the Rapid Reset Attack in the Go language packages. Security Bulletin https://access.redhat.com/security/vulnerabilities/RHSB-2023-003

    Source: BSI WID Portal

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    IBMPlanning Analytics
    • 2.0
    • 2.1
    • —
    • —
    nettynetty
    • ≥ 4.2.0.Final, < 4.2.15.Final
    • < 4.1.135.Final
    • —
    • 4.1.135.Final
    akkahttp_server
    • < 10.5.3
    • 10.5.3
    amazonopensearch_data_prepper
    • < 2.5.0
    • 2.5.0
    apacheapisix
    • < 3.6.1
    • 3.6.1
    apachesolr
    • < 9.4.0
    • 9.4.0
    apachetomcat
    • 10.1.0 – ≤ 10.1.13
    • 11.0.0
    • 8.5.0 – ≤ 8.5.93
    • 9.0.0 – ≤ 9.0.80
    • —
    • —
    • —
    • —
    apachetraffic_server
    • 8.0.0 – < 8.1.9
    • 9.0.0 – < 9.2.3
    • 8.1.9
    • 9.2.3
    appleswiftnio_http\/2
    • < 1.28.0
    • 1.28.0
    caddyservercaddy
    • < 2.7.5
    • 2.7.5
    ciscobusiness_process_automation
    • < 3.2.003.009
    • 3.2.003.009
    ciscoconnected_mobile_experiences
    • < 11.1
    • 11.1
    ciscocrosswork_data_gateway
    • 5.0.0 – < 5.0.2
    • < 4.1.3
    • 5.0.2
    • 4.1.3
    ciscocrosswork_situation_manager
    • —
    • —
    ciscocrosswork_zero_touch_provisioning
    • < 6.0.0
    • 6.0.0
    ciscodata_center_network_manager
    • —
    • —
    ciscoenterprise_chat_and_email
    • —
    • —
    ciscoexpressway
    • < x14.3.3
    • x14.3.3
    ciscoiot_field_network_director
    • < 4.11.0
    • 4.11.0
    ciscoprime_access_registrar
    • < 9.3.3
    • 9.3.3
    ciscoprime_cable_provisioning
    • < 7.2.1
    • 7.2.1
    ciscoprime_infrastructure
    • < 3.10.4
    • 3.10.4
    ciscoprime_network_registrar
    • < 11.2
    • 11.2
    ciscosecure_dynamic_attributes_connector
    • < 2.2.0
    • 2.2.0
    ciscosecure_firewall_threat_defense
    • < 7.4.2
    • 7.4.2
    ciscosecure_malware_analytics
    • < 2.19.2
    • 2.19.2
    ciscotelepresence_video_communication_server
    • < x14.3.3
    • x14.3.3
    ciscoultra_cloud_core_-_policy_control_function
    • 2024.01.0
    • < 2024.01.0
    • —
    • 2024.01.0
    ciscoultra_cloud_core_-_serving_gateway_function
    • < 2024.02.0
    • 2024.02.0
    ciscoultra_cloud_core_-_session_management_function
    • < 2024.02.0
    • 2024.02.0
    ciscounified_attendant_console_advanced
    • —
    • —
    ciscounified_contact_center_domain_manager
    • —
    • —
    ciscounified_contact_center_enterprise
    • —
    • —
    ciscounified_contact_center_enterprise_-_live_data_server
    • < 12.6.2
    • 12.6.2
    ciscounified_contact_center_management_portal
    • —
    • —
    denah2o
    • < 2023-10-10
    • 2023-10-10
    eclipsejetty
    • 10.0.0 – < 10.0.17
    • 11.0.0 – < 11.0.17
    • 12.0.0 – < 12.0.2
    • < 9.4.53
    • 10.0.17
    • 11.0.17
    • 12.0.2
    • 9.4.53
    Distribution and container packages (2)

    Downstream packages (e.g. Bitnami, Debian, Ubuntu, Red Hat). Versions refer to the distribution, not the vendor.

    Distribution and container packages
    Affected versionsFixed in
    bitnamivarnish
    • 6.1.0
    • 7.4.0
    • —
    • —
    From bundled advisories, not CVE-specific (81)

    Product list of a bundled advisory that does not state which product this CVE affects.

    Products from bundled advisories
    Affected versionsFixed in
    —HTTP/2 protocol implementations (servers, proxies, CDNs)
    • Most HTTP/2 implementations; see each vendor's advisory
    • —
    ApacheTomcat
    • < 8.5.94
    • < 9.0.81
    • 8.5.94
    • 9.0.81
    AtlassianBamboo Data Center LTS
    • < 10.2.22
    • < 10.2.23
    • < 12.1.10
    • < 12.1.11
    • 10.2.22
    • 10.2.23
    • 12.1.10
    • 12.1.11
    AtlassianBamboo LTS
    • < 10.2.21
    • < 12.1.9
    • 10.2.21
    • 12.1.9
    AtlassianBitbucket Data Center
    • < 10.4.2
    • < 10.4.3
    • 10.4.2
    • 10.4.3
    AtlassianBitbucket Data Center LTS
    • < 10.2.6
    • < 10.2.7
    • < 9.4.23
    • < 9.4.24
    • 10.2.6
    • 10.2.7
    • 9.4.23
    • 9.4.24
    AtlassianBitbucket LTS
    • < 10.3.2
    • < 9.4.22
    • 10.3.2
    • 9.4.22
    AtlassianConfluence
    • 8.5
    • < 7.19.20
    • < 8.5.7
    • < 8.8.1
    • —
    • 7.19.20
    • 8.5.7
    • 8.8.1
    AtlassianConfluence Data Center LTS
    • < 10.2.15
    • < 10.2.17
    • < 10.2.18
    • < 9.2.23
    • < 9.2.24
    • < 9.2.25
    • 10.2.15
    • 10.2.17
    • 10.2.18
    • 9.2.23
    • 9.2.24
    • 9.2.25
    AtlassianConfluence LTS
    • < 10.2.14
    • < 9.2.22
    • 10.2.14
    • 9.2.22
    AtlassianCrucible
    • < 4.9.12
    • < 4.9.13
    • < 4.9.14
    • 4.9.12
    • 4.9.13
    • 4.9.14
    AtlassianFisheye
    • < 4.9.12
    • < 4.9.13
    • < 4.9.14
    • 4.9.12
    • 4.9.13
    • 4.9.14
    AtlassianJira Data Center LTS
    • < 10.3.24
    • < 10.3.25
    • < 11.3.10
    • < 11.3.11
    • 10.3.24
    • 10.3.25
    • 11.3.10
    • 11.3.11
    AtlassianJira LTS
    • < 10.3.23
    • < 11.3.8
    • 10.3.23
    • 11.3.8
    AtlassianJira Service Management Data Center LTS
    • < 10.3.25
    • < 11.3.11
    • 10.3.25
    • 11.3.11
    BroadcomBrocade SANnav
    • < 2.3.0a
    • < 2.3.1
    • 2.3.0a
    • 2.3.1
    DellData Protection Advisor
    • < 19.12
    • 19.12
    DellNetWorker
    • vProxy<19.10
    • vProxy<19.9.0.4
    • —
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebiandebian_linux10.0
    Linuxdebiandebian_linux11.0
    Linuxdebiandebian_linux12.0
    Linuxredhatenterprise_linux8.0
    Linuxredhatenterprise_linux6.0
    Linuxredhatenterprise_linux9.0
    Linuxdebianjetty9bookworm
    Linuxdebianjetty9bullseye
    Linuxdebiannettybookworm
    Linuxdebiannettybullseye
    Linuxdebiannghttp2bookworm
    Linuxdebiannghttp2bullseye
    Linuxdebiantomcat10bookworm
    Linuxdebiantomcat9bullseye
    Linuxdebiantrafficserverbookworm
    Linuxdebiantrafficserverbullseye
    Mobileciscoios_xe—
    Mobileciscoios_xr—
    Otherfedoraprojectfedora38
    Otherfedoraprojectfedora37
    Otherciscofog_director—
    Othercisconx-os—
    Othersiemensruggedcom_ape1808_firmware—
    Otherciscosecure_web_appliance_firmware—

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited
    CSA/SingCERTActive Exploitation of Zero-Day HTTP/2 Vulnerability (opens in a new tab)CSA/SingCERTactively exploited
    GitHubbcdannyboy/CVE-2023-44487 (opens in a new tab)github.comPoC (publicly reported)reported, not verified—
    PoC-in-GitHub (nomi-sec)rapid-reset-check (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)CVE-2023-44487-HTTP2-DoS-Rapid-Reset-Exploit (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)CVE-2023-44487-dos (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)http2-security-lab (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

    • github.comnetty/netty/security/advisories/GHSA-hvcg-qmg6-jm4cweb, x_refsource_CONFIRM, Vendor advisory
    • NVD (NIST)vuln/detail/CVE-2026-50020advisory
    • github.comnetty/nettypackage
    • github.comnetty/netty/releases/tag/netty-4.1.135.Finalweb, x_refsource_MISC, Release notes
    • github.comnetty/netty/releases/tag/netty-4.2.15.Finalweb, x_refsource_MISC, Release notes
    • ibm.comsupport/pages/node/7283486Vendor advisory, Patch
    • github.comnetty/netty/security/advisories/GHSA-c2gf-v879-257jweb, x_refsource_CONFIRM
    • NVD (NIST)vuln/detail/CVE-2026-48043advisory
    • security.access.redhat.comdata/csaf/v2/vex/2026/cve-2026-48043.jsonweb, x_sadp-csaf-vex
    • bugzilla.redhat.comRHBZ#2488442web, Issue tracking, x_refsource_REDHAT
    • access.redhat.comsecurity/cve/CVE-2026-48043web, Vulnerability database, x_refsource_REDHAT
    • access.redhat.comerrata/RHSA-2026:48151web, Vendor advisory, x_refsource_REDHAT
    • access.redhat.comerrata/RHSA-2026:48124web, Vendor advisory, x_refsource_REDHAT
    • access.redhat.comerrata/RHSA-2026:41951web, Vendor advisory, x_refsource_REDHAT
    • access.redhat.comerrata/RHSA-2026:37390web, Vendor advisory, x_refsource_REDHAT
    • access.redhat.comerrata/RHSA-2026:36820web, Vendor advisory, x_refsource_REDHAT
    • access.redhat.comerrata/RHSA-2026:34608web, Vendor advisory, x_refsource_REDHAT
    • access.redhat.comerrata/RHSA-2026:26586web, Vendor advisory, x_refsource_REDHAT
    • access.redhat.comerrata/RHSA-2026:26018web, Vendor advisory, x_refsource_REDHAT
    • access.redhat.comerrata/RHSA-2026:26017web, Vendor advisory, x_refsource_REDHAT

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Product identifiers remappedNVD

      Product mapping changed:
      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Product configurationchanged
      OR *cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:* versions from (excluding) 7.4.2
      OR *cpe:2.3:a:cisco:secure_firewall_threat_defense:*:*:*:*:*:*:*:* versions from (excluding) 7.4.2

      Source identifier: nvd@nist.gov

    Linked CVEs

    Linked CVEs
    MediumCVE-2026-50020Netty: HTTP Request/Response Smuggling5.3—
    HighCVE-2026-48043Netty: Missing Release of Memory after Effective Lifetime7.5—
    MediumCVE-2026-47244Netty HTTP/2: Advertised MAX_CONCURRENT_STREAMS are not enforced5.3—
    HighCVE-2026-13365IBM Planning Analytics Local is affected by security vulnerabilities7.1—
    CriticalCVE-2023-44487HTTP/2 Rapid Reset Attack Vulnerability7.5Actively exploited
    Embed badge

    Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.

    Badge preview for CVE-2023-44487
    <a href="https://intel.neosec.eu/en/cve/CVE-2023-44487"><img src="https://intel.neosec.eu/badge/cve/CVE-2023-44487.svg?lang=en" alt="CVE-2023-44487 – NEOSEC Intel" height="20"></a>