CVE-2026-34518: aio-libs aiohttp · Information Exposure
Affects aio-libs aiohttpSource CVE Database V5
Not known to be exploited · CVSS 2.7 Low : upgrade to 3.13.4 when convenient.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.13.4
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:UExploitation evidence
Disclosed: evidence found.
CVE published 2 Apr 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 29 Oct 2026.
What to do
Upgrade aio-libs aiohttp to 3.13.4.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| aio-libsaiohttp | Affected
| Fixed in
|
PyPIaiohttppkg:pypi/aiohttpOther 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 aiohttp to version 3.13.4 or later, where this issue has been patched. No other mitigation is indicated or necessary.
Description
CVE-2026-34518 is a low-severity vulnerability in aiohttp versions prior to 3.13.4 where the Authorization header is improperly handled during redirects to a different origin. Specifically, while the Authorization header is dropped as intended, the Cookie and Proxy-Authorization headers are retained, potentially exposing sensitive information to unauthorized actors. This issue has been addressed in aiohttp version 3.13.4.