CVE catalog

CVE-2021-21240

python-httplib2: CVE-2021-21240

Severity: High · CVSS 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: Jan 9, 2021, 12:00:00 AM UTC
Source: [NVD] · [CVE record]
EPSS: 3.63% · Oct 27, 2026

httplib2 is a comprehensive HTTP client library for Python. In httplib2 before version 0.19.0, a malicious server which responds with long series of "\xa0" characters in the "www-authenticate" header may cause Denial of Service (CPU burn while parsing header) of the httplib2 client accessing said server. This is fixed in version 0.19.0 which contains a new implementation of auth headers parsing using the pyparsing library.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	python-httplib2	sid	`0.32.0-1`	fixed
Debian	python-httplib2	forky	`0.32.0-1`	fixed
Debian	python-httplib2	trixie	`0.22.0-1+deb13u1`	fixed
Debian	python-httplib2	trixie-security	`0.22.0-1+deb13u1`	fixed
Debian	python-httplib2	bookworm	`0.20.4-3`	fixed
Debian	python-httplib2	bookworm-security	`0.20.4-3+deb12u1`	fixed
Ubuntu	python-httplib2	14.04	`0.8-2`	vulnerable
Ubuntu	python-httplib2	14.04	`0.8-2build1`	vulnerable
Ubuntu	python-httplib2	16.04	`0.9+dfsg-2`	vulnerable
Ubuntu	python-httplib2	16.04	`0.9.1+dfsg-1`	vulnerable
Ubuntu	python-httplib2	18.04	`0.9.2+dfsg-1`	vulnerable
Ubuntu	python-httplib2	18.04	`0.9.2+dfsg-1ubuntu0.1`	vulnerable
Ubuntu	python-httplib2	18.04	`0.9.2+dfsg-1ubuntu0.2`	vulnerable
Ubuntu	python-httplib2	18.04	`0.9.2+dfsg-1ubuntu0.3`	vulnerable
Ubuntu	python-httplib2	20.04	`0.11.3-2`	vulnerable
Ubuntu	python-httplib2	20.04	`0.11.3-2build1`	vulnerable
Ubuntu	python-httplib2	20.04	`0.14.0-1`	vulnerable
Ubuntu	python-httplib2	20.04	`0.14.0-1ubuntu1`	vulnerable
Ubuntu	python-httplib2	22.04	`0.18.1-3ubuntu1`	vulnerable
Ubuntu	python-httplib2	22.04	`0.20.2-2`	vulnerable
Ubuntu	python-httplib2	22.04	`0.20.2-2ubuntu0.1`	vulnerable

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	python-httplib2	source	sid	`0.20.2-1`	not yet assigned	Not reported	[982738]
Debian	python-httplib2	source	forky	`0.20.2-1`	not yet assigned	Not reported	[982738]
Debian	python-httplib2	source	trixie	`0.20.2-1`	not yet assigned	Not reported	[982738]
Debian	python-httplib2	source	bookworm	`0.20.2-1`	not yet assigned	Not reported	[982738]

[Debian bug #982738]

OpenFactory catalog packages

Matching against OpenFactory catalog package versions is in progress.

[Debian 12 (Bookworm)]

[python3-httplib2]Unknown
Source package: [python-httplib2]
Details (4)
- 0.20.4-3 · all · bookworm
  Fixed · Fixed: 0.20.2-1
  dsa · python-httplib2 · debian · bookworm; dsa · python-httplib2 · debian · 12
- 0.20.4-3 · all · bookworm
  Fixed · Fixed: 0.20.2-1
  dsa · python-httplib2 · debian · bookworm; dsa · python-httplib2 · debian · 12
- 0.20.4-3+deb12u1 · all · bookworm-security
  Fixed · Fixed: 0.20.2-1
  dsa · python-httplib2 · debian · bookworm; dsa · python-httplib2 · debian · 12
- 0.20.4-3+deb12u1 · all · bookworm-security
  Fixed · Fixed: 0.20.2-1
  dsa · python-httplib2 · debian · bookworm; dsa · python-httplib2 · debian · 12

[Debian 13 (Trixie)]

[python3-httplib2]Unknown
Source package: [python-httplib2]
Details (4)
- 0.22.0-1 · all · trixie
  Fixed · Fixed: 0.20.2-1
  dsa · python-httplib2 · debian · 13
- 0.22.0-1 · all · trixie
  Fixed · Fixed: 0.20.2-1
  dsa · python-httplib2 · debian · 13
- 0.22.0-1+deb13u1 · all · trixie-security
  Fixed · Fixed: 0.20.2-1
  dsa · python-httplib2 · debian · 13
- 0.22.0-1+deb13u1 · all · trixie-security
  Fixed · Fixed: 0.20.2-1
  dsa · python-httplib2 · debian · 13

Observed: Oct 23, 2026, 5:54:32 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]