LowCVE-2026-57198

    Asterisk: Possible RED T.140 Heap Buffer Overflow (CVE-2026-57198)

    Published Last modified Sources: BSI, CVE.org

    What is affected, what to do

    Asterisk is an open source private branch exchange and telephony toolkit. In affected deployments, an authenticated attacker may cause a `T.140 RED` heap buffer overflow using carefully crafted packets, potentially allowing remote code execution or causing Asterisk to crash.

    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 57.4

    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
    67.84 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
    57.4
    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
    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-122

    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. In affected deployments, an authenticated attacker may cause a `T.140 RED` heap buffer overflow using carefully crafted packets, potentially allowing remote code execution or causing Asterisk to crash. The `chan_sip` channel driver must be installed and configured, and its `textsupport` option must be enabled; `textsupport` defaults to no. `The chan_sip driver was deprecated in Asterisk 20 and completely removed in all later versions.` Repository comparisons verify patch containment in Asterisk 20.20.1, 21.12.3, 22.10.1 and 23.4.1, and Certified Asterisk 20.7-cert11 and 22.8-cert3. The affected release-track scope remains unresolved: structured metadata includes later release tracks even though the advisory says the required `chan_sip` driver was removed there.

    Source: BSI CSAF, BSI WID Portal, NVD (NIST), cvelistv5

    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
    • —
    Open SourceAsterisk
    • < 20.20.1
    • < 23.4.1
    • < 22.8-cert3
    • < 21.12.3
    • < 20.7-cert11
    • < 22.10.1
    • 20.20.1
    • 23.4.1
    • 22.8-cert3
    • 21.12.3
    • 20.7-cert11
    • 22.10.1

    Vendors and products

    Weakness classes (CWE)

    • CWE-122Heap-based Buffer Overflow

      Variant

      A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

      Entry at MITRE CWE-122

    References & sources

    • github.comasterisk/asterisk/commit/0601c33d4edf8c8f221de91cead59460fb1e71…x_refsource_MISC
    • github.comasterisk/asterisk/commit/111487298a954a029daae941eac423f0609b12…x_refsource_MISC
    • github.comasterisk/asterisk/commit/536218a86b797996e8e8844deacc8207de3737…x_refsource_MISC
    • github.comasterisk/asterisk/commit/a89b61d7c756f816c7fa5327ead9e889f15312…x_refsource_MISC
    • github.comasterisk/asterisk/commit/eaa108c68a32c080d7a168ef1d8bf784d5d830…x_refsource_MISC
    • github.comasterisk/asterisk/commit/eef894282be203cb9e6d8e9692e9c360a0b569…x_refsource_MISC
    • github.comasterisk/asterisk/commit/fde69a1f3ff17f507a1578ae27b528f43ceb5e…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/security/advisories/GHSA-vfhr-r9x9-c687x_refsource_CONFIRM
    • 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. ReceivedGitHub

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

      Weakness type: CWE-122

      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. In affected deployments, an authenticated attacker may cause a `T.140 RED` heap buffer overflow using carefully crafted packets, potentially allowing remote code execution or causing Asterisk to crash. The `chan_sip` channel driver must be installed and configured, and its `textsupport` option must be enabled; `textsupport` defaults to no. `The chan_sip driver was deprecated in Asterisk 20 and completely removed in all later versions.` Repository comparisons verify patch containment in Asterisk 20.20.1, 21.12.3, 22.10.1 and 23.4.1, and Certified Asterisk 20.7-cert11 and 22.8-cert3. The affected release-track scope remains unresolved: structured metadata includes later release tracks even though the advisory says the required `chan_sip` driver was removed there.
      CVSSadded
      —
      AV:N/AC:L/AT:P/PR:L/UI:N/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-122
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/57xxx/CVE-2026-57198.json">CVE-2026-57198</a>
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/0601c33d4edf8c8f221de91cead59460fb1e7180
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/111487298a954a029daae941eac423f0609b1261
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/536218a86b797996e8e8844deacc8207de373701
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/a89b61d7c756f816c7fa5327ead9e889f1531202
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/eaa108c68a32c080d7a168ef1d8bf784d5d830f4
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/eef894282be203cb9e6d8e9692e9c360a0b569b4
      Referenceadded
      —
      https://github.com/asterisk/asterisk/commit/fde69a1f3ff17f507a1578ae27b528f43ceb5efd
      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-vfhr-r9x9-c687
      Referenceadded
      —
      https://github.com/asterisk/asterisk/tree/24.0.0-pre1

      Source identifier: security-advisories@github.com

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