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TI-2026-79986 Aliases CVE-2026-115776GHSA-53xc-49m8-p798

Unbounded buffer in Twisted IRC server allows remote denial of service

Priority LOW 39CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-400.

Summary

Twisted, an event-based Python framework for internet applications, is affected before 26.10.0rc1. Its IRC protocol handler keeps all bytes received without a line feed in a per-connection buffer and applies no maximum line length, a case of CWE-400. An unauthenticated remote attacker can keep sending data before any PASS, NICK or USER command, which grows the buffer until the shared server process runs out of memory and drops all users.

Written with Claude Haiku 5.5 from the sources below · 2026-10-30

Description from the CNA

Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.words.protocols.irc.IRC.dataReceived retains all bytes received without a line feed in its per-connection buffer and applies no maximum line length. The twisted.words.service.IRCUser server subclass inherits this behavior, and buffering occurs before PASS, NICK, or USER authentication commands. An unauthenticated connection can continuously grow the buffer until the shared server process runs out of memory and drops all users. This issue is fixed in version 26.10.0rc1.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00501 43rd percentileScored 2026-11-07
Fix Partial twisted (twisted): 26.10.0rc1Twisted (PyPI): 26.10.0rc1Red Hat: 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
twistedtwistedbefore 26.10.0rc126.10.0rc1Patch availableCNA
—Twisted (PyPI)before 26.10.0rc126.10.0rc1Patch availableGHSA-53xc-49m8-p798
  • twisted Vendortwisted Affected before 26.10.0rc1 Fixed in 26.10.0rc1 Patch available CNA
  • Twisted (PyPI) Vendor— Affected before 26.10.0rc1 Fixed in 26.10.0rc1 Patch available GHSA-53xc-49m8-p798

Remediation

Upgrade Twisted to version 26.10.0rc1, which fixes the PyPI package. Red Hat rates the issue Important and lists Red Hat Ansible Automation Platform 2 as affected with no fix plan available.

Written with Claude Haiku 5.5 from the sources below · 2026-10-30

  • Fix · CNA twisted (twisted) Fixed in 26.10.0rc1
  • Fix · GHSA-53xc-49m8-p798 Twisted (PyPI) Fixed in 26.10.0rc1 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Ansible Automation Platform 2AffectedNo fix yet
Not affected: 2 products
  • Red Hat Ansible Automation Platform 2
  • Red Hat OpenStack Platform 16.2

Timeline

  1. 2026-10-23 Threatist record created from CVE-2026-115776
  2. 2026-10-23 Alias added: GHSA-53xc-49m8-p798
  3. 2026-10-23 Fix available: PyPI/[email protected] · GHSA-53xc-49m8-p798
  4. 2026-10-23 CVSS score added · GHSA-53xc-49m8-p798
  5. 2026-10-23 Weakness changed · GHSA-53xc-49m8-p798
  6. 2026-10-23 6 new references · GHSA-53xc-49m8-p798
  7. 2026-10-24 Priority changed: MEDIUM → LOW
  8. 2026-10-24 Affected versions changed · Red Hat
  9. 2026-10-24 CVSS score added · Red Hat
  10. 2026-10-25 EPSS moved to the below the 50th percentile
  11. 2026-10-29 Affected versions changed · Red Hat
  12. 2026-10-30 CISA SSVC decision points changed

References

Other 6

  • TI-2026-79985 Unauthenticated memory exhaustion in Twisted domish XML parser CVSS 4.0HIGH 8.7
  • TI-2026-30612 Twisted: Denial of Service (DoS) in twisted.names via Crafted DNS Compression Pointer Chains CVSS 3.1HIGH 7.5
  • TI-2022-06090 Buffer Overflow in Twisted CVSS 3.1HIGH 7.5
  • TI-2024-27732 twisted.web has disordered HTTP pipeline response CVSS 3.1HIGH 8.3
  • TI-2024-27854 HTML injection in HTTP redirect body CVSS 3.1MEDIUM 6.1
  • TI-2026-79989 HTTP request smuggling in Twisted web via bare CR or LF in headers CVSS 3.1MEDIUM 5.4
See all 21 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences