LowCVE-2026-83813

    Twisted: DNS Response Spoofing in twisted.names Due to Missing Source Address Validation (CVE-2026-83813)

    Published Last modified Sources: Msrc Update Guide, CVE.org, OSV, Hersteller

    What is affected, what to do

    Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.names.dns.DNSDatagramProtocol accepts a UDP DNS response for a pending query when its 16-bit transaction ID matches but does not verify that the response came from the queried host and port.

    Update Twisted to version 26.7.0rc1.

    Affected
    • Twisted lt *..26.7.0rc1
    Fixed in
    • Twisted 26.7.0rc1

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

    Metrics

    3.1

    Priority

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

    Source: Vendor (CNA), CVSS v3

    3.1

    CVSS v3

    Severity Low on the scale from 0 to 10.

    Source: Msrc Update Guide, CVE.org, OSV, Hersteller

    0.1 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 1.5

    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
    45.52 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
    3.1 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
    3.1
    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
    0.1 %
    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
    1.5
    Low — this CVE sits in the lower 10% of all CVEs scored today.
    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: proof of concept · not automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 29 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-346

    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

    Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.names.dns.DNSDatagramProtocol accepts a UDP DNS response for a pending query when its 16-bit transaction ID matches but does not verify that the response came from the queried host and port. An attacker able to deliver a packet to the resolver's listening port with the correct transaction ID can inject a forged answer. The standard twisted.names.client.Resolver uses a new random source port for each query, increasing off-path attack complexity, while applications that reuse a DNSDatagramProtocol instance expose only the transaction-ID search space after the first query. A successful forgery can redirect hostname resolution and enable mail interception, server-side request forgery, or man-in-the-middle positioning. This issue is fixed in version 26.10.0rc1.

    Source: Microsoft Security Update Guide, cvelistv5, NVD (NIST), OSV (Open Source Vulnerabilities), GitHub Security Advisories

    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
    twistedtwisted
    • < 26.7.0rc1
    • 26.7.0rc1
    pipTwisted
    • <= 26.4.0
    • 26.10.0rc1
    pypitwisted
    • 17.9.0
    • —
    • 22.2.0rc1
    • 2.1.0
    • 24.7.0
    • 19.2.0rc2
    • 19.10.0rc1
    • 14.0.1
    • 24.10.0
    • 8.1.0
    • 13.0.0
    • 19.10.0
    • 16.1.1
    • 23.8.0rc1
    • 16.7.0rc2
    • 1.1.1
    • 23.10.0
    • 22.8.0
    • 16.6.0
    • 19.7.0rc1
    • 16.2.0
    • 18.7.0rc2
    • 1.1.0
    • 16.4.1
    • 13.1.0
    • 14.0.2
    • 15.0.0
    • 19.2.0
    • 24.10.0rc1
    • 22.4.0
    • 18.9.0rc1
    • 16.0.0
    • 18.7.0rc1
    • 12.2.0
    • 13.2.0
    • 20.3.0rc1
    • 1.0.7
    • 15.4.0
    • 26.4.0rc2
    • 2.5.0
    • 17.5.0
    • 24.3.0
    • 19.2.1
    • 16.5.0rc1
    • 21.7.0rc1
    • 16.1.0
    • —
    • 26.10.0rc1
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —

    Vendors and products

    Weakness classes (CWE)

    • CWE-346Origin Validation Error

      Class

      The product does not properly verify that the source of data or communication is valid.

      Entry at MITRE CWE-346

    References & sources

    • github.comtwisted/twisted/commit/b53e1c3477c209b5609a1c74cf9e48373b5879acx_refsource_MISC, web
    • github.comtwisted/twisted/pull/12700x_refsource_MISC, web
    • github.comtwisted/twisted/releases/tag/twisted-26.10.0rc1x_refsource_MISC, web
    • github.comtwisted/twisted/security/advisories/GHSA-jj36-9pvh-vj5rx_refsource_CONFIRM, web
    • NVD (NIST)vuln/detail/CVE-2026-83813advisory
    • github.comtwisted/twistedpackage

    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: proof of concept, automatable: no

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://github.com/twisted/twisted/security/advisories/GHSA-jj36-9pvh-vj5r
      SSVC assessmentadded
      —
      {"id":"CVE-2026-83813","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-29T18:15:10.606448Z"}

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

    2. ReceivedGitHub

      CVSS V3.1: AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

      Weakness type: CWE-346

      Description added or changed

      Show 8 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.names.dns.DNSDatagramProtocol accepts a UDP DNS response for a pending query when its 16-bit transaction ID matches but does not verify that the response came from the queried host and port. An attacker able to deliver a packet to the resolver's listening port with the correct transaction ID can inject a forged answer. The standard twisted.names.client.Resolver uses a new random source port for each query, increasing off-path attack complexity, while applications that reuse a DNSDatagramProtocol instance expose only the transaction-ID search space after the first query. A successful forgery can redirect hostname resolution and enable mail interception, server-side request forgery, or man-in-the-middle positioning. This issue is fixed in version 26.10.0rc1.
      CVSSadded
      —
      AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
      Weakness type (CWE)added
      —
      CWE-346
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/83xxx/CVE-2026-83813.json">CVE-2026-83813</a>
      Referenceadded
      —
      https://github.com/twisted/twisted/commit/b53e1c3477c209b5609a1c74cf9e48373b5879ac
      Referenceadded
      —
      https://github.com/twisted/twisted/pull/12700
      Referenceadded
      —
      https://github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1
      Referenceadded
      —
      https://github.com/twisted/twisted/security/advisories/GHSA-jj36-9pvh-vj5r

      Source identifier: security-advisories@github.com

    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-2026-83813
    <a href="https://intel.neosec.eu/en/cve/CVE-2026-83813"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-83813.svg?lang=en" alt="CVE-2026-83813 – NEOSEC Intel" height="20"></a>