CVE-2026-64847: agronholm anyio · Unthrottled Resource Allocation
Affects agronholm anyioSource CVE Database V5
Not known to be exploited · CVSS 6.8 Medium : upgrade to 4.14.2 when convenient.
Data as of 2 Nov 2026, 22:58 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.14.2
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 18 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2 Nov 2026.
What to do
Upgrade agronholm anyio to 4.14.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| agronholmanyio | Affected
| Fixed in
|
PyPIanyiopkg:pypi/anyioOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade AnyIO to version 4.14.2 or later, where this issue is fixed. No other specific mitigations are indicated. Since this is a library-level fix, applying the official update resolves the vulnerability.
Description
AnyIO versions prior to 4.14.2 contain a resource allocation vulnerability where process-pool workers' standard error pipes are not drained by the parent process. This can cause the pipe to fill and block the worker if it writes enough data to stderr, leading to indefinite blocking of the process-pool call. The issue affects applications running untrusted or faulty worker code that produces substantial standard error output. The vulnerability is fixed in AnyIO version 4.14.2.
References
- github.com/agronholm/anyio/security/advisories/GHSA-5p39-cfhj-2xmp (opens in a new tab)
- github.com/agronholm/anyio/pull/1207 (opens in a new tab)
- github.com/agronholm/anyio/commit/f1b7301c8264b0d2e8d24a5788fd29e93dea4040 (opens in a new tab)
- github.com/agronholm/anyio/releases/tag/4.14.2 (opens in a new tab)