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Vulnerabilities

Vulnerability · CVE-2026-115778

Twisted: Unauthenticated Remote Denial of Service in the Twisted conch Telnet Transport via an Unbounded Subnegotiation Buffer

Published Oct 23, 2026 · catalog updated Oct 24, 2026 · Red Hat Red Hat Enterprise Linux

Last checked Nov 6, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-115778. EPSS is 0.54%. Act only if a listed version of Red Hat Red Hat Enterprise Linux is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.54%
Remediation
Advisory link
Affected products
Debian:12 twisted · Debian:13 twisted · Debian:14 twisted · pypi twisted

Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.conch.telnet.Telnet.dataReceived appends every byte received after IAC SB to a persistent subnegotiation buffer until IAC SE is received, without applying a maximum length. Telnet option negotiation occurs before authentication, so an unauthenticated peer can omit the terminator and continuously grow the buffer. The resulting memory exhaustion can terminate the process and every service it hosts. This issue is fixed in version 26.10.0rc1.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Debian:12 twisted22.4.0-4, 22.4.0-4+deb12u1, 23.10.0-1
  • Debian:13 twisted24.11.0-1, 25.5.0-1, 25.5.0-2
  • Debian:14 twisted24.11.0-1, 25.5.0-1, 25.5.0-2
  • pypi twistedversion unspecified

How to fix CVE-2026-115778

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-115778. EPSS is 0.54%. Act only if a listed version of Red Hat Red Hat Enterprise Linux is installed.

Which versions are affected?

Compare what you have installed with 22.4.0-4, 22.4.0-4+deb12u1, 23.10.0-1, 24.11.0-1, 25.5.0-1, 25.5.0-2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-770: Allocation of Resources Without Limits or Throttling. EPSS 0.54%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Debian security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 23, 2026 · Red Hat Security Data

    Detected

    twisted: twisted: Denial of Service via memory exhaustion during Telnet negotiation

  2. Oct 24, 2026 · Trivy Vulnerability DB

    Updated

    Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.conch.telnet.Telnet.dataReceived appends every byte received after IAC SB to a persistent subnegotiation buffer until IAC SE is received, without applying a maximum length. Telnet option negotiation occurs before authentication, so an unauthenticated peer can omit the terminator and

Sources

  • CVE.orgVulnerability recordCVE-2026-115778

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-115778

    30-day exploitation probability 0.54%

    first.org
  • GitLab Advisory DatabasePackage advisoryCVE-2026-115778

    An allocation-without-limits vulnerability (CWE-770) in the Twisted conch telnet transport lets any unauthenticated remote peer exhaust server memory over a single connection. When the peer opens a telnet subnegotiation with IAC SB and then streams bytes without ever sending the IAC SE terminator, every byte is appended to a per-connection buffer that has no maximum length. The buffer persists acr

    advisories.gitlab.com
  • Red Hat Security DataVendor advisoryCVE-2026-115778

    twisted: twisted: Denial of Service via memory exhaustion during Telnet negotiation

    access.redhat.com
  • Trivy Vulnerability DBPackage advisoryDEBIAN-CVE-2026-115778

    Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.conch.telnet.Telnet.dataReceived appends every byte received after IAC SB to a persistent subnegotiation buffer until IAC SE is received, without applying a maximum

    osv.dev

References

Freshness

Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 6, 2026
  • GitLab Advisory DatabaseOct 27, 2026
  • Red Hat Security DataOct 26, 2026
  • CVE.orgOct 24, 2026
  • Trivy Vulnerability DBOct 24, 2026