6.9

CVE-2026-59881: AIOHTTP: WebSocket client accepts compressed frames without negotiated permessage-deflate

Deferred
AliasesGHSA-mq44-7p77-q5h7PYSEC-2026-3547UBUNTU-CVE-2026-59881
Published 30-07-2026Last modified 30-07-2026

Vulnerability summary

CVE-2026-59881 is a medium (CVSS 6.9) Improper Input Validation vulnerability in aio-libs aiohttp. EPSS estimates a 0.52% chance of exploitation in the next 30 days, higher than 44.4% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 6.9, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
6.9/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.52%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 5 · Related 6
OPENSUSE-SU-2026:11467-1OPENSUSE-SU-2026:21687-1SUSE-SU-2026:23571-1SUSE-SU-2026:4031-1SUSE-SU-2026:4113-1CGA-FHXM-R4HW-H773

Timeline

  1. 30-07-2026
    PublishedVulnerability first disclosed.
  2. 30-07-2026
    Last modifiedVulnerability information updated.

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.2, the WebSocket client accepts and decompresses frames with the RSV1 bit set even when the permessage-deflate extension was not negotiated, allowing a malicious server to cause unexpected CPU and memory consumption. This issue is fixed in version 3.14.2.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.52%

Chance of exploitation in the next 30 days

Percentile

44%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.52% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard25 products
  • airflow-2All versions (No fix recorded)
  • airflow-3< 3.3.1-r1 | < 3.3.0-r4
  • airflow-3-iamguarded-compatAll versions (No fix recorded)
  • airflow-core-2< 2.11.2-r6
  • apache-beam-python-3.11-sdk< 2.75.0-r2
Wolfi8 products
  • airflow-3< 3.3.1-r1 | < 3.3.0-r4
  • airflow-3-iamguarded-compatAll versions (No fix recorded)
  • dask-kubernetes< 2026.3.0-r11
  • kserve< 0.20.0-r7
  • kserve-localmodel< 0.20.0-r7
Aio-libs1 product
Debian1 product
  • python-aiohttpAll versions (No fix recorded) | < 3.8.4-1+deb12u2 | < 3.14.3-1
PyPI1 product
  • aiohttp< 3.14.2
Ubuntu1 product
  • python-aiohttpAll versions (No fix recorded)

6 vendors · 37 products

References

12 links
Show all 12 references