LowCVE-2026-57196

    Asterisk: Reflected XSS in Phone Provisioning HTTP Error Pages (CVE-2026-57196)

    Published Last modified Sources: BSI, CVE.org

    What is affected, what to do

    Asterisk is an open source private branch exchange and telephony toolkit. Prior to Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3, an unauthenticated attacker may use reflected cross-site scripting in `phone provisioning HTTP error pages` to retrieve an authorized user's `AMI session cookie` and impersonate that user when `res_phoneprov` is enabled.

    Update Asterisk to version 20.20.1, Asterisk Certified-asterisk to version 20.7-cert11.

    Affected
    • Asterisk gte 21.0.0-pre1, < 21.12.3..*
    • Asterisk lt *..20.20.1
    • Asterisk Certified-asterisk gte 22.8-cert1-pre1, < 22.8-cert3..*
    • Asterisk Certified-asterisk lt *..20.7-cert11
    Fixed in
    • Asterisk 20.20.1
    • Asterisk Certified-asterisk 20.7-cert11

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

    Metrics

    2.3

    Priority

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

    Source: Vendor (CNA), CVSS v4

    2.3

    CVSS v4

    Severity Low on the scale from 0 to 10.

    Source: BSI, CVE.org

    0.8 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 55.4

    Show all metrics
    Severity
    Low
    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
    66.04 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
    no public PoC known
    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
    2.3 Methodology
    CVSS v4

    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
    2.3
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.8 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    55.4
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    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
    —
    Published
    CISA assessment (SSVC)
    Exploitation: none known · not automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 26 October 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-79

    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
    Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
    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
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    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

    Asterisk is an open source private branch exchange and telephony toolkit. Prior to Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3, an unauthenticated attacker may use reflected cross-site scripting in `phone provisioning HTTP error pages` to retrieve an authorized user's `AMI session cookie` and impersonate that user when `res_phoneprov` is enabled. The Asterisk HTTP web server, Asterisk Manager Interface (AMI), and AMI access via HTTP must all be enabled; each is disabled by default. The attacker must be able to connect to the HTTP server, which binds only to `127.0.0.1` by default even when enabled, and must convince the authorized user to click a malicious link. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3.

    Source: BSI WID Portal, BSI CSAF, NVD (NIST), cvelistv5, CVE.org (MITRE)

    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
    asteriskasterisk
    • ≥ 21.0.0-pre1, < 21.12.3
    • < 20.20.1
    • —
    • 20.20.1
    asteriskcertified-asterisk
    • < 20.7-cert11
    • ≥ 22.8-cert1-pre1, < 22.8-cert3
    • 20.7-cert11
    • —

    Vendors and products

    Weakness classes (CWE)

    • CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

      Base

      The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

      Entry at MITRE CWE-79

    References & sources

    • github.comasterisk/asterisk/security/advisories/GHSA-4pgv-j3mr-3rcpx_refsource_CONFIRM
    • github.comasterisk/asterisk/commit/4373f8174bf71c467fc9db96036126d30425b9…x_refsource_MISC
    • github.comasterisk/asterisk/commit/4b360a61d649a7c12b1021aa554642322ee28c…x_refsource_MISC
    • github.comasterisk/asterisk/commit/60c23d8b56b2cf93caceb527e07654b16f3883…x_refsource_MISC
    • github.comasterisk/asterisk/commit/87399593cda601ae3670bf890bdb32f78e881b…x_refsource_MISC
    • github.comasterisk/asterisk/commit/9cff8e62fbd9e7db87c233de3335047df88877…x_refsource_MISC
    • github.comasterisk/asterisk/commit/dc43c5b32a3a216da4c9e95388fbadaca3e78b…x_refsource_MISC
    • github.comasterisk/asterisk/commit/e6998409f73f49959d0062c695bb9a2f611af5…x_refsource_MISC
    • github.comasterisk/asterisk/releases/tag/20.20.1x_refsource_MISC
    • github.comasterisk/asterisk/releases/tag/21.12.3x_refsource_MISC
    • github.comasterisk/asterisk/releases/tag/22.10.1x_refsource_MISC
    • github.comasterisk/asterisk/releases/tag/23.4.1x_refsource_MISC
    • github.comasterisk/asterisk/releases/tag/certified-20.7-cert11x_refsource_MISC
    • github.comasterisk/asterisk/releases/tag/certified-22.8-cert3x_refsource_MISC
    • github.comasterisk/asterisk/tree/24.0.0-pre1x_refsource_MISC

    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. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-57196","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-26T19:44:31.470203Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. ReceivedGitHub

      CVSS V4.0: AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

      Weakness type: CWE-79

      Description added or changed

      Show 19 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      Asterisk is an open source private branch exchange and telephony toolkit. Prior to Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3, an unauthenticated attacker may use reflected cross-site scripting in `phone provisioning HTTP error pages` to retrieve an authorized user's `AMI session cookie` and impersonate that user when `res_phoneprov` is enabled. The Asterisk HTTP web server, Asterisk Manager Interface (AMI), and AMI access via HTTP must all be enabled; each is disabled by default. The attacker must be able to connect to the HTTP server, which binds only to `127.0.0.1` by default even when enabled, and must convince the authorized user to click a malicious link. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3.
      CVSSadded
      —
      AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
      Weakness type (CWE)added
      —
      CWE-79
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/57xxx/CVE-2026-57196.json">CVE-2026-57196</a>
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/4373f8174bf71c467fc9db96036126d30425b9e8
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/4b360a61d649a7c12b1021aa554642322ee28c10
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/60c23d8b56b2cf93caceb527e07654b16f388343
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/87399593cda601ae3670bf890bdb32f78e881bf3
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/9cff8e62fbd9e7db87c233de3335047df88877d0
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/dc43c5b32a3a216da4c9e95388fbadaca3e78bc8
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/e6998409f73f49959d0062c695bb9a2f611af5ac
      Referenceadded
      —
      https://github.com/asterisk/asterisk/releases/tag/20.20.1
      Referenceadded
      —
      https://github.com/asterisk/asterisk/releases/tag/21.12.3
      Referenceadded
      —
      https://github.com/asterisk/asterisk/releases/tag/22.10.1
      Referenceadded
      —
      https://github.com/asterisk/asterisk/releases/tag/23.4.1
      Referenceadded
      —
      https://github.com/asterisk/asterisk/releases/tag/certified-20.7-cert11
      Referenceadded
      —
      https://github.com/asterisk/asterisk/releases/tag/certified-22.8-cert3
      Referenceadded
      —
      https://github.com/asterisk/asterisk/security/advisories/GHSA-4pgv-j3mr-3rcp
      Referenceadded
      —
      https://github.com/asterisk/asterisk/tree/24.0.0-pre1

      Source identifier: security-advisories@github.com

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