CVE-2026-115778

HIGHPre-NVD 7.57.5
EchelonGraph scoreHIGH confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-10-23. A secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 4 sources updated this week

Also known asEUVD-2026-109151 (ENISA EUVD) · GHSA-cwm5-jh59-mwxr (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
7.5
EG Score
7.5HIGHhigh confidence
EG Risk
49
EG Risk 49/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.5%
EPSS %ILE
45th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

October 23, 2026

Last Modified

October 26, 2026

Advisory Details (5)

Auto-updated Oct 23, 2026
Patch available. Sources: github, github_pr, github_commit, github_release.
GitHub release Patch Available

Towncrier 26.10.0rc1

Patch available: twisted/twisted twisted-26.10.0rc1 (pre-release)

https://github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1
GitHub commit Patch Available

commit 5d91cc66a359 (twisted/twisted)

Patch available: twisted/twisted twisted-26.10.0rc1 (contains commit 5d91cc66a359)

https://github.com/twisted/twisted/commit/5d91cc66a3591faba758a80a1479e0103602facc
GitHub commit Patch Available

commit 073ba878c6c0 (twisted/twisted)

Patch available: twisted/twisted twisted-26.10.0rc1 (contains commit 073ba878c6c0)

https://github.com/twisted/twisted/commit/073ba878c6c07d569cb61abc5ae76d46eff1b529
GitHub pull request Patch Available

#12706 twisted.conch.telnet: bound the subnegotiation buffer to prevent a memory DoS

Patch available: twisted/twisted twisted-26.10.0rc1 (PR #12750 merged 2026-08-22)

https://github.com/twisted/twisted/pull/12750
GitHub advisoryMentions a patch (unverified)

Unauthenticated Remote Denial of Service in the Twisted conch Telnet Transport via an Unbounded Subnegotiation Buffer · Advisory · twisted/twisted · GitHub

https://github.com/twisted/twisted/security/advisories/GHSA-cwm5-jh59-mwxr

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
pipTwisted @ 26.10.0rc1 (fixes <= 26.4.0)—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
twisted1.0.1 ... 9.0.0 (111 versions)
  • every version up to 26.10.0rc1: fixed in 26.10.0rc1
—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 20× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-11-02 11:38 UTCEG score recompute
  2. 2026-11-02 11:38 UTCVendor advisory
  3. 2026-11-02 11:38 UTCGHSA enrichmentGHSA-cwm5-jh59-mwxr · GitHub severity HIGH · GitHub CVSS 7.5
  4. 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  5. 2026-11-01 07:59 UTCGHSA enrichmentGHSA-cwm5-jh59-mwxr · GitHub severity HIGH · GitHub CVSS 7.5
  6. 2026-11-01 07:59 UTCEG score recompute
  7. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  8. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  9. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  10. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  11. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  12. 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  13. 2026-10-26 14:08 UTCEG score recompute
  14. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  15. 2026-10-25 14:50 UTCEG score recompute
  16. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.7% · 54th percentile
  17. 2026-10-23 21:31 UTCEG score recompute
  18. 2026-10-23 21:00 UTCEG score recompute
  19. 2026-10-23 20:26 UTCEG score recomputeFirst assessed: 7.5 HIGH
  20. 2026-10-23 20:24 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-115778?
CVE-2026-115778 is a high-severity vulnerability; its CVE record was published on October 23, 2026. 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…
When was the CVE record for CVE-2026-115778 published?
The CVE record for CVE-2026-115778 was published on October 23, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 26, 2026; the record at its source may have been updated since.
Is CVE-2026-115778 actively exploited?
CVE-2026-115778 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (45th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-115778?
CVE-2026-115778 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-115778?
A fix for CVE-2026-115778 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-115778 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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