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🛡️ CVE-2026-34515 — aiohttp

🟠 CVSS 7.5 — High ✅ No Known Exploit CWE-36 OSV
7.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

AIOHTTP affected by UNC SSRF/NTLMv2 Credential Theft/Local File Read in static resource handler on Windows

Summary

On Windows the static resource handler may expose information about a NTLMv2 remote path.

Impact

If an application is running on Windows, and using aiohttp's static resource handler (not recommended in production), then it may be possible for an attacker to extract the hash from an NTLMv2 path and then extract the user's credentials from there.

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Patch: https://github.com/aio-libs/aiohttp/commit/0ae2aa076c84573df83fc1fdc39eec0f5862fe3d

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. Rated impact: confidentiality high, integrity none, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Attack requirements: None — no deployment-specific condition has to hold.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: None.
  • Availability impact: None.

Weakness class

CVE-2026-34515 is classified as CWE-36: Absolute Path Traversal. The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize absolute path sequences such as "/abs/path" that can resolve to a location that is outside of that directory.

Affected software

CVE-2026-34515 is recorded against 1 package.

  • aiohttp (fixed in 3.13.4)

Timeline and source

Published on 1 April 2026 and last revised on 13 July 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from OSV.

References

github.com (Web)
nvd.nist.gov (Advisory)
github.com (Web)
github.com (Package)
github.com (Web)

Other advisories for this package

aiohttp has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-36: Absolute Path Traversal) in other software:

CVE-2026-34515 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity HIGH
CVSS Score 7.5
CVSS Vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U
CWE CWE-36
Public Exploit ✅ No
Source OSV
Published 2026-04-01
Updated 2026-08-20
Modified 2026-07-13

Affected Packages

Software From version Fixed in
aiohttp — 3.13.4

Site Security Check

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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