CVE catalog

CVE-2026-111749

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, Host-Only scope on an existing parent-domain cookie can be removed by a subdomain. A user who accesses

[CVE catalog]

Severity: Medium · CVSS 4.2CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
Published: Oct 19, 2026, 5:04:42 PM UTC
Updated: Oct 19, 2026, 5:17:04 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.38% · Oct 25, 2026

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, Host-Only scope on an existing parent-domain cookie can be removed by a subdomain. A user who accesses an untrusted subdomain can consequently have host-only protections stripped from cookies, although impact is limited when applications do not reflect those cookies to a browser. This issue is fixed in version 3.14.4.

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-aiohttp	sid	`3.14.3-1`	vulnerable
Debian	python-aiohttp	forky	`3.14.3-1`	vulnerable
Debian	python-aiohttp	trixie	`3.11.16-1+deb13u1`	vulnerable
Debian	python-aiohttp	trixie-security	`3.11.16-1+deb13u1`	vulnerable
Debian	python-aiohttp	bookworm	`3.8.4-1+deb12u1`	vulnerable
Debian	python-aiohttp	bookworm-security	`3.8.4-1+deb12u1`	vulnerable
Ubuntu	python-aiohttp	pro	`3.11.16-1`	vulnerable
Ubuntu	python-aiohttp	pro	`3.13.1-1`	vulnerable
Ubuntu	python-aiohttp	pro	`3.13.3-3`	vulnerable
Ubuntu	python-aiohttp	pro	`3.13.3-3ubuntu1`	vulnerable
Ubuntu	python-aiohttp	pro	`3.13.3-3ubuntu1+esm1`	vulnerable
Ubuntu	python-aiohttp	26.10	`3.13.3-3ubuntu1`	vulnerable
Ubuntu	python-aiohttp	26.10	`3.14.1-4`	vulnerable
Ubuntu	python-aiohttp	26.10	`3.14.1-5`	vulnerable
Ubuntu	python-aiohttp	26.10	`3.14.3-1`	vulnerable

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	python-aiohttp	source	sid	`(unfixed)`	not yet assigned	Not reported	[1151687]
Debian	python-aiohttp	source	forky	`(unfixed)`	not yet assigned	Not reported	[1151687]
Debian	python-aiohttp	source	trixie	`(unfixed)`	not yet assigned	Not reported	[1151687]
Debian	python-aiohttp	source	bookworm	`(unfixed)`	not yet assigned	Not reported	[1151687]

[Debian bug #1151687]

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[python3-aiohttp]Affected
Source package: [python-aiohttp]
Details (4)
- 3.8.4-1+deb12u1 · amd64 · bookworm
  Affected
  nvd · python-aiohttp · debian · bookworm; nvd · python-aiohttp · debian · 12
- 3.8.4-1+deb12u1 · arm64 · bookworm
  Affected
  nvd · python-aiohttp · debian · bookworm; nvd · python-aiohttp · debian · 12
- 3.8.4-1+deb12u1 · amd64 · bookworm-security
  Affected
  nvd · python-aiohttp · debian · bookworm; nvd · python-aiohttp · debian · 12
- 3.8.4-1+deb12u1 · arm64 · bookworm-security
  Affected
  nvd · python-aiohttp · debian · bookworm; nvd · python-aiohttp · debian · 12
[python-aiohttp-doc]Affected
Source package: [python-aiohttp]
Details (4)
- 3.8.4-1+deb12u1 · all · bookworm
  Affected
  nvd · python-aiohttp · debian · bookworm; nvd · python-aiohttp · debian · 12
- 3.8.4-1+deb12u1 · all · bookworm
  Affected
  nvd · python-aiohttp · debian · bookworm; nvd · python-aiohttp · debian · 12
- 3.8.4-1+deb12u1 · all · bookworm-security
  Affected
  nvd · python-aiohttp · debian · bookworm; nvd · python-aiohttp · debian · 12
- 3.8.4-1+deb12u1 · all · bookworm-security
  Affected
  nvd · python-aiohttp · debian · bookworm; nvd · python-aiohttp · debian · 12

[Debian 13 (Trixie)]

[python3-aiohttp]Affected
Source package: [python-aiohttp]
Details (4)
- 3.11.16-1+deb13u1 · amd64 · trixie
  Affected
  nvd · python-aiohttp · debian · 13
- 3.11.16-1+deb13u1 · arm64 · trixie
  Affected
  nvd · python-aiohttp · debian · 13
- 3.11.16-1+deb13u1 · amd64 · trixie-security
  Affected
  nvd · python-aiohttp · debian · 13
- 3.11.16-1+deb13u1 · arm64 · trixie-security
  Affected
  nvd · python-aiohttp · debian · 13
[python-aiohttp-doc]Affected
Source package: [python-aiohttp]
Details (4)
- 3.11.16-1+deb13u1 · all · trixie
  Affected
  nvd · python-aiohttp · debian · 13
- 3.11.16-1+deb13u1 · all · trixie
  Affected
  nvd · python-aiohttp · debian · 13
- 3.11.16-1+deb13u1 · all · trixie-security
  Affected
  nvd · python-aiohttp · debian · 13
- 3.11.16-1+deb13u1 · all · trixie-security
  Affected
  nvd · python-aiohttp · debian · 13

Observed: Oct 27, 2026, 4:09:06 AM UTC

References

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