CVE-2026-63349

HIGHPre-NVD 7.07.0—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.0 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 99% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.0Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio. In 4.14.0, AnyIO accepts the POSIX extra_groups argument in anyio.run_process() and anyio.open_process(), but open_process() forwards the group argument to the backend instead of extra_groups. A caller that supplies extra_groups=[] to clear inherited supplementary groups can therefore launch a child that retains the parent process groups, undermining a privilege-dropping boundary. If group is also supplied, the integer group value is passed where an iterable of supplementary groups is expected and the launch can fail with TypeError. This issue affects POSIX applications that rely on AnyIO subprocess helpers to launch less-privileged child processes. This issue is fixed in version 4.14.2.

CVSS v3
7.0
EG Score
7.0(medium)
EG Risk
36(Track)
EG Risk 36/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity70% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
1%
KEV
Not listed

Published

September 18, 2026

Last Modified

September 18, 2026

Advisory Details (4)

Auto-updated Sep 18, 2026
Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available

4.14.2

Patch available: agronholm/anyio 4.14.2

https://github.com/agronholm/anyio/releases/tag/4.14.2
github_commit Patch Available

commit eb562e6462ee (agronholm/anyio)

Patch available: agronholm/anyio 4.14.2 (contains commit eb562e6462ee)

https://github.com/agronholm/anyio/commit/eb562e6462ee46b1904e50b02ce00a858cdeb200
github_pr Patch Available

Fixed `extra_groups` not being passed to backend `open_process()`

Patch available: agronholm/anyio 4.14.2 (PR #1209 merged 2026-07-08)

https://github.com/agronholm/anyio/pull/1209
github Patch Available

AnyIO run_process/open_process ignores extra_groups and can retain parent supplementary groups · Advisory · agronholm/anyio · GitHub

https://github.com/agronholm/anyio/security/advisories/GHSA-3w57-8xmc-8v26

Vendor Advisories for CVE-2026-63349(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 4× in last 7d / 4× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

  1. 2026-09-20 02:22 UTCEG score recompute
  2. 2026-09-18 17:26 UTCEG score recompute
  3. 2026-09-18 17:04 UTCEG score recompute
  4. 2026-09-18 17:04 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-63349?
CVE-2026-63349 is a high vulnerability published on September 18, 2026. AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio. In 4.14.0, AnyIO accepts the POSIX extragroups argument in anyio.runprocess() and anyio.openprocess(), but openprocess() forwards the group argument to the backend instead of…
When was CVE-2026-63349 disclosed?
CVE-2026-63349 was first published in the National Vulnerability Database on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63349 actively exploited?
CVE-2026-63349 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 98.6% of all scored CVEs.
What is the CVSS score of CVE-2026-63349?
CVE-2026-63349 has a CVSS v3 base score of 7.0 (NVD).
How do I remediate CVE-2026-63349?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63349, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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