CVE-2026-111749
AIOHTTP: Cookie from subdomain can remove Host-Only Scope from existing cookies
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
AIOHTTP: Cookie from subdomain can remove Host-Only Scope from existing cookies
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.
- Record
CVE-2026-111749- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-565
- Updated
- 2026-11-02
EUVDEUVD-2026-104485
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.
- Record
EUVD-2026-104485- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-gx76-c99x-2c96
AIOHTTP: Cookie from subdomain can remove Host-Only Scope from existing cookies
Summary
A subdomain can remove the Host-Only flag from an existing cookie to a parent domain.
Impact
A user accessing untrusted subdomains could see their Host-Only protections stripped from cookies. Given most usecases won't reflect these cookies to a browser, the impact is limited.
- Record
GHSA-gx76-c99x-2c96- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-565
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-111749- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-565
- Updated
- 2026-11-02
OSV
AIOHTTP: Cookie from subdomain can remove Host-Only Scope from existing cookies
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.
- Record
CVE-2026-111749- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-565
- Updated
- 2026-11-04
OSVDEBIAN-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 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.
- Record
DEBIAN-CVE-2026-111749- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Updated
- 2026-11-02
Show 6 moreShow less
OSVGHSA-gx76-c99x-2c96
AIOHTTP: Cookie from subdomain can remove Host-Only Scope from existing cookies
Summary
A subdomain can remove the Host-Only flag from an existing cookie to a parent domain.
Impact
A user accessing untrusted subdomains could see their Host-Only protections stripped from cookies. Given most usecases won't reflect these cookies to a browser, the impact is limited.
- Record
GHSA-gx76-c99x-2c96- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-565
- Updated
- 2026-11-02
OSVOESA-2026-4558
python-aiohttp security update
Async http client/server framework (asyncio).
Security Fix(es):
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the Secure attribute for a shared cookie is not enforced. An attacker can consequently cause a shared cookie marked Secure to be sent with an unencrypted request. This issue is fixed in version 3.14.4.(CVE-2026-111063)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, keepalive timeout handling is absent during the initial portion of a request. An attacker can keep an idle connection open indefinitely before sending any request data, consuming server connection capacity. This issue is fixed in version 3.14.4.(CVE-2026-111064)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, Max-Age processing can overflow and skip closing a connection. An attacker can consequently exhaust the connection pool temporarily until garbage collection resolves the connections. This issue is fixed in version 3.14.4.(CVE-2026-111065)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. From 2.0.0 until 3.14.4, multipart request processing can retain an unbounded number of open file descriptors. An unauthenticated attacker can consequently exhaust file descriptors with specially crafted multipart requests when a handler uses Request.post(). This issue is fixed in version 3.14.4.(CVE-2026-111066)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, an attacker can send an absolute-form request that causes Request.scheme to use attacker-controlled request-target scheme data instead of the connection protocol. Applications that use Request.scheme for security decisions can consequently be tricked into treating an unencrypted connection as encrypted or an encrypted connection as unencrypted. This issue is fixed in version 3.14.4.(CVE-2026-111748)
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.(CVE-2026-111749)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the pure Python parser accepts ambiguous HTTP request framing. An unauthenticated attacker can consequently smuggle requests when an application uses AIOHTTP_NO_EXTENSIONS or otherwise runs without a standard wheel and an intermediary interprets the framing differently. This issue is fixed in version 3.14.4.(CVE-2026-111750)
- Record
OESA-2026-4558- CVSS 4.0
- 8.2 High
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-02
OSVOESA-2026-4559
python-aiohttp security update
Async http client/server framework (asyncio).
Security Fix(es):
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the Secure attribute for a shared cookie is not enforced. An attacker can consequently cause a shared cookie marked Secure to be sent with an unencrypted request. This issue is fixed in version 3.14.4.(CVE-2026-111063)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, keepalive timeout handling is absent during the initial portion of a request. An attacker can keep an idle connection open indefinitely before sending any request data, consuming server connection capacity. This issue is fixed in version 3.14.4.(CVE-2026-111064)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, Max-Age processing can overflow and skip closing a connection. An attacker can consequently exhaust the connection pool temporarily until garbage collection resolves the connections. This issue is fixed in version 3.14.4.(CVE-2026-111065)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. From 2.0.0 until 3.14.4, multipart request processing can retain an unbounded number of open file descriptors. An unauthenticated attacker can consequently exhaust file descriptors with specially crafted multipart requests when a handler uses Request.post(). This issue is fixed in version 3.14.4.(CVE-2026-111066)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, an attacker can send an absolute-form request that causes Request.scheme to use attacker-controlled request-target scheme data instead of the connection protocol. Applications that use Request.scheme for security decisions can consequently be tricked into treating an unencrypted connection as encrypted or an encrypted connection as unencrypted. This issue is fixed in version 3.14.4.(CVE-2026-111748)
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.(CVE-2026-111749)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the pure Python parser accepts ambiguous HTTP request framing. An unauthenticated attacker can consequently smuggle requests when an application uses AIOHTTP_NO_EXTENSIONS or otherwise runs without a standard wheel and an intermediary interprets the framing differently. This issue is fixed in version 3.14.4.(CVE-2026-111750)
- Record
OESA-2026-4559- CVSS 4.0
- 8.2 High
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-02
OSVOESA-2026-4560
python-aiohttp security update
Async http client/server framework (asyncio).
Security Fix(es):
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the Secure attribute for a shared cookie is not enforced. An attacker can consequently cause a shared cookie marked Secure to be sent with an unencrypted request. This issue is fixed in version 3.14.4.(CVE-2026-111063)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, keepalive timeout handling is absent during the initial portion of a request. An attacker can keep an idle connection open indefinitely before sending any request data, consuming server connection capacity. This issue is fixed in version 3.14.4.(CVE-2026-111064)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, Max-Age processing can overflow and skip closing a connection. An attacker can consequently exhaust the connection pool temporarily until garbage collection resolves the connections. This issue is fixed in version 3.14.4.(CVE-2026-111065)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. From 2.0.0 until 3.14.4, multipart request processing can retain an unbounded number of open file descriptors. An unauthenticated attacker can consequently exhaust file descriptors with specially crafted multipart requests when a handler uses Request.post(). This issue is fixed in version 3.14.4.(CVE-2026-111066)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, an attacker can send an absolute-form request that causes Request.scheme to use attacker-controlled request-target scheme data instead of the connection protocol. Applications that use Request.scheme for security decisions can consequently be tricked into treating an unencrypted connection as encrypted or an encrypted connection as unencrypted. This issue is fixed in version 3.14.4.(CVE-2026-111748)
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.(CVE-2026-111749)
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the pure Python parser accepts ambiguous HTTP request framing. An unauthenticated attacker can consequently smuggle requests when an application uses AIOHTTP_NO_EXTENSIONS or otherwise runs without a standard wheel and an intermediary interprets the framing differently. This issue is fixed in version 3.14.4.(CVE-2026-111750)
- Record
OESA-2026-4560- CVSS 4.0
- 8.2 High
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-02
OSVUBUNTU-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 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.
- Record
UBUNTU-CVE-2026-111749- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
OSVAZL-110692 No score
CVE-2026-111749 affecting package python-aiohttp 3.6.2-3
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.
- Record
AZL-110692- Updated
- 2026-11-05
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
aiohttpPyPI |
through 3.14.3 | 3.14.4 |
python-aiohttpAzure Linux:3 |
through 3.6.2-3 | None known |
python-aiohttpDebian:12 |
All versions, plus listed versions 3.10.0-13.10.1-13.10.10-13.10.10-23.10.11-1 Show 29 moreShow less3.10.3-13.10.3-23.10.3-33.10.4-13.10.5-13.10.6-13.10.8-13.11.15-13.11.16-13.12.15-13.13.0-13.13.1-13.13.3-13.13.3-23.13.3-33.13.5-13.14.0-13.14.1-13.14.1-23.14.1-33.14.1-43.14.1-53.14.3-13.8.4-13.8.4-1+deb12u13.8.5-13.8.6-13.9.1-13.9.5-1 |
None known |
python-aiohttpDebian:13 |
All versions, plus listed versions 3.11.16-13.11.16-1+deb13u13.12.15-13.13.0-13.13.1-1 Show 11 moreShow less3.13.3-13.13.3-23.13.3-33.13.5-13.14.0-13.14.1-13.14.1-23.14.1-33.14.1-43.14.1-53.14.3-1 |
None known |
python-aiohttpDebian:14 |
All versions, plus listed versions 3.11.16-13.12.15-13.13.0-13.13.1-13.13.3-1 Show 10 moreShow less3.13.3-23.13.3-33.13.5-13.14.0-13.14.1-13.14.1-23.14.1-33.14.1-43.14.1-53.14.3-1 |
None known |
aiohttpPyPI |
before 3.14.4, plus listed versions 0.10.10.00.10.10.10.20.11.0 Show 45 moreShow less0.12.00.13.00.13.10.14.00.14.10.14.20.14.30.14.40.15.00.15.10.15.20.15.30.16.00.16.10.16.20.16.30.16.40.16.50.16.60.17.00.17.10.17.20.17.30.17.40.18.00.18.10.18.20.18.30.18.40.19.00.20.20.00.20.10.20.20.21.00.21.10.21.20.21.40.21.50.21.60.22.00.22.0a00.22.0b00.22.0b10.22.0b2 |
3.14.4 |
python-aiohttpopenEuler:24.03-LTS-SP4 From an advisory covering 7 CVEs |
before 3.14.3-2.oe2403sp4 | 3.14.3-2.oe2403sp4 |
python-aiohttpopenEuler:24.03-LTS-SP1 From an advisory covering 7 CVEs |
before 3.14.3-2.oe2403sp1 | 3.14.3-2.oe2403sp1 |
python-aiohttpopenEuler:24.03-LTS-SP3 From an advisory covering 7 CVEs |
before 3.14.3-2.oe2403sp3 | 3.14.3-2.oe2403sp3 |
python-aiohttpUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 0.17.2-10.17.4-10.17.4-1build10.20.2-10.20.2-1ubuntu0.1~esm1 |
None known |
Show 6 moreShow less
| Package | Affected | Fixed |
|---|---|---|
python-aiohttpUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 2.2.3-1build12.2.3-22.3.6-13.0.1-13.0.1-1ubuntu0.1~esm1 Show 4 moreShow less3.0.1-1ubuntu0.1~esm43.0.1-1ubuntu0.1~esm53.0.1-1ubuntu0.1~esm63.0.1-1ubuntu0.1~esm7 |
None known |
python-aiohttpUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 3.5.4-13.5.4-1build13.6.1-13.6.2-13.6.2-1build1 Show 7 moreShow less3.6.2-1ubuntu0.1~esm13.6.2-1ubuntu13.6.2-1ubuntu1+esm13.6.2-1ubuntu1+esm33.6.2-1ubuntu1+esm43.6.2-1ubuntu1+esm53.6.2-1ubuntu1+esm6 |
None known |
python-aiohttpUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 3.7.4-13.7.4-1build23.8.1-33.8.1-43.8.1-4build1 Show 4 moreShow less3.8.1-4ubuntu0.23.8.1-4ubuntu0.2+esm13.8.1-4ubuntu0.2+esm23.8.1-4ubuntu0.2+esm3 |
None known |
python-aiohttpUbuntu:Pro:24.04:LTS |
All versions, plus listed versions 3.8.4-13.9.1-13.9.1-1build13.9.1-1ubuntu0.13.9.1-1ubuntu0.1+esm13.9.1-1ubuntu0.1+esm23.9.1-1ubuntu0.1+esm3 |
None known |
python-aiohttpUbuntu:26.10 |
All versions, plus listed versions 3.13.3-3ubuntu13.14.1-43.14.1-53.14.3-1 |
None known |
python-aiohttpUbuntu:Pro:26.04:LTS |
All versions, plus listed versions 3.11.16-13.13.1-13.13.3-33.13.3-3ubuntu13.13.3-3ubuntu1+esm1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected | OSV | |
| facts | OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-111749 is a low vulnerability (CVSS 2.3) in Aio-libs Aiohttp, published October 19, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.38%, the 32nd percentile. Fixed in aiohttp 3.14.4.
References
github.com/aio-libs/aiohttp/security/advisories/GHSA-gx76-c99x-2c96
nvd.nist.gov/vuln/detail/CVE-2026-111749
Show 13 moreShow less
security-tracker.debian.org/tracker/CVE-2026-111749
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-4558
ubuntu.com/security/CVE-2026-111749
cve.org/CVERecord?id=CVE-2026-111749
Left out here: 260 versions. The JSON record has them.