Suricata smb: some SMB flows can cause resource exhaustion (CVE-2026-63448)
Published Last modified Sources: CVE.org
What is affected, what to do
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.17 and 8.0.6, the SMB parser can retain force-completed transactions on flows where Suricata sees payload in only one direction, including async-oneside flows, because cleanup waits for inspection in the unseen direction.
Update OISF Suricata to version 7.0.17.
- Affected
- OISF Suricata
gte 8.0.0, < 8.0.6..* - OISF Suricata
lt *..7.0.17
- OISF Suricata
- Fixed in
- OISF Suricata
7.0.17
- OISF Suricata
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Metrics
7.5
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
5.9
CVSS v3
Severity Medium on the scale from 0 to 10.
Source: CVE.org
0.4 %
EPSS score
Low — model estimates < 1% exploitation likelihood.
Source: FIRST EPSS, percentile 37.8
Show all metrics
- Severity
- High
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- 70.18 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- 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- 5.9
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- 0.4 %
- 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- 37.8
- 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
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-400, CWE-401, CWE-407
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- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
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
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.17 and 8.0.6, the SMB parser can retain force-completed transactions on flows where Suricata sees payload in only one direction, including async-oneside flows, because cleanup waits for inspection in the unseen direction. The transaction creation paths in rust/src/smb can exceed the intended SMB_MAX_TX bound, and cleanup repeatedly scans the growing list. Sustained one-directional SMB traffic can therefore cause unbounded per-flow state and CPU and memory exhaustion. This issue is fixed in versions 8.0.6 and 7.0.17.
Source: cvelistv5, NVD (NIST)
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| OISF | suricata |
|
|
| oisf | suricata |
|
|
Weakness classes (CWE)
CWE-400Uncontrolled Resource Consumption
Class
The product does not properly control the allocation and maintenance of a limited resource.
Entry at MITRE CWE-400CWE-401Missing Release of Memory after Effective Lifetime
Variant
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
Entry at MITRE CWE-401CWE-407Inefficient Algorithmic Complexity
Class
An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
Entry at MITRE CWE-407
References & sources
- github.comOISF/suricata/security/advisories/GHSA-hvvj-c8xx-9g35x_refsource_CONFIRM
- github.comOISF/suricata/commit/755d6c3061de4d7ba97f0ed31cdc17ab8cab4476x_refsource_MISC
- github.comOISF/suricata/commit/7ec9d72d28b9370712cf77a5b9d40d6b5db27cb4x_refsource_MISC
- github.comOISF/suricata/commit/88adab8bd3d62912941647ab65032d5ec75c893ax_refsource_MISC
- github.comOISF/suricata/commit/9a54a043516e644bb7b9d34117a91977f950a281x_refsource_MISC
- github.comOISF/suricata/commit/bc39274a638d1cca2391cfa4891c8b6c255ff9cex_refsource_MISC
- github.comOISF/suricata/commit/c8f68b0e4f9e721dca1c9ed6e08597c6964c7ac3x_refsource_MISC
- github.comOISF/suricata/releases/tag/suricata-7.0.17x_refsource_MISC
- github.comOISF/suricata/releases/tag/suricata-8.0.6x_refsource_MISC
- redmine.openinfosecfoundation.orgissues/8629x_refsource_MISC
Reanalysis & status changes
Chronological NVD audit events for this CVE — reanalyses, CVSS updates, CPE diffs.
Initial Analysisnvd@nist.gov
- CVSS V3.1: after AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CPE Configuration: after OR *cpe:2.3:a:oisf:suricata:*:*:*:*:*:*:*:* versions from (including) 8.0.0 up to (excluding) 8.0.6 *cpe:2.3:a:oisf:suricata:*:*:*:*:*:*:*:* versions up to (excluding) 7.0.17
- Reference Type: after GitHub, Inc.: https://github.com/OISF/suricata/commit/755d6c3061de4d7ba97f0ed31cdc17ab8cab4476 Types: Patch
- Reference Type: after GitHub, Inc.: https://github.com/OISF/suricata/commit/7ec9d72d28b9370712cf77a5b9d40d6b5db27cb4 Types: Patch
CVE Modified134c704f-9b21-4f2e-91b3-4a467353bcc0
- SSVC: after {"id":"CVE-2026-63448","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalI…
New CVE Receivedsecurity-advisories@github.com
- Description: after Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.17 and 8.0.6, the SMB parser can retain force-completed transactions on flows where Suricata sees payload in only one direction, including async-oneside flows, because cleanup waits for inspection in the unseen direction. The transaction creation paths in rust/src/smb can exceed the intended SMB_MAX_TX bound, and cleanup repeatedly scans the growing list. Sustained one-directional SMB traffic can therefore cause unbounded per-flow state and CPU and memory exhaustion. This issue is fixed in versions 8.0.6 and 7.0.17.
- CVSS V3.1: after AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- CWE: after CWE-407
- CWE: after CWE-400
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<a href="https://intel.neosec.eu/en/cve/CVE-2026-63448"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-63448.svg?lang=en" alt="CVE-2026-63448 – NEOSEC Intel" height="20"></a>