CyberSecBulletin
CVE-2026-59939NVD status: Modified

httplib2: Improper Handling of Highly Compressed Data (Data Amplification)

Published Updated By the CyberSecBulletin desk

CVE-2026-59939 is a high-severity improper handling of highly compressed data (data amplification) vulnerability in httplib2, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected httplib2 versions: < 0.32.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.66% chance of exploitation within 30 days, higher than 52% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of httplib2 you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Httplib2httplib2< 0.32.0Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (github.com).

Official description

httplib2 is a comprehensive HTTP client library for Python. Prior to 0.32.0, httplib2 performs unbounded decompression of HTTP response bodies encoded with Content-Encoding: gzip or deflate in _decompressContent in httplib2/init.py, allowing a malicious or compromised HTTP server to return a small compressed payload that expands to an arbitrarily large size in memory and causes MemoryError or OOM-kill in the client process. This issue is fixed in version 0.32.0.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Handling of Highly Compressed Data (Data Amplification)

The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.

More Improper Handling of Highly Compressed Data (Data Amplification) vulnerabilities (CWE-409)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Improper Handling of Highly Compressed Data (Data Amplification) vulnerabilities

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