CVE-2026-54274

Summary

If an attacker sends large incomplete websocket frame payloads, it may be possible to bypass the usual size limits on memory use.

Impact

If a web application has WebSocket endpoints, it may be possible for an attacker to execute a DoS attack through excessive memory use.

Patch: https://github.com/aio-libs/aiohttp/commit/14b6ee851fb16ec199acb950de0c82d476799e7d

Async http client/server framework (asyncio).

Security Fix(es):

No limit was present on the number of pipelined requests that could be queued. Impact An attacker may be able to use pipelined requests to use excessive amounts of memory, potentially leading to DoS.(CVE-2026-54273)

If an attacker sends large incomplete websocket frame payloads, it may be possible to bypass the usual size limits on memory use. Impact If a web application has WebSocket endpoints, it may be possible for an attacker to execute a DoS attack through excessive memory use(CVE-2026-54274)

If an application makes multiple requests to the same domain, but with different per-request server_hostname parameters, then the later calls may succeed by reusing the existing connection when they should have been rejected due to the TLS SNI check.(CVE-2026-54275)

If the client follows a redirect (the default option) to an attacker controlled domain, the attacker may be able to extract the auth digest.

This likely requires an open redirect vulnerability or similar on the target domain for an attacker to be able to execute. Further, the attacker is only receiving the digest, so should only be able to extract the user's credentials if the cryptography is weak or there is some kind of password reuse.(CVE-2026-54276)

It is possible to bypass the max_line_size check in parts of an HTTP request in the C parser. Impact If using the optimized C parser (the default in pre-built wheels), then an attacker may be able to send oversized lines through the HTTP parser and use an excessive amount of memory, potentially leading to DoS.(CVE-2026-54277)

An attacker may be able to send a compressed payload in specific situations that could be decompressed into memory, potentially leading to DoS (a zip bomb edge case).(CVE-2026-54278)

Host-only cookies If you save a cookie and later restore it, you lose the host-only status. CookieJar.save()CookieJar.load() affects host-only cookies loaded from disk that may be sent to subdomains that should previously have been banned(CVE-2026-54279)

Payload resources are not closed correctly when a client disconnects in the middle of a write. Impact If a payload is using an open file or similar limited resource, then an attacker may be able to cause resource starvation temporarily until garbage collection or similar closes the file.(CVE-2026-54280)

Async http client/server framework (asyncio).

Security Fix(es):

No limit was present on the number of pipelined requests that could be queued. Impact An attacker may be able to use pipelined requests to use excessive amounts of memory, potentially leading to DoS.(CVE-2026-54273)

If an attacker sends large incomplete websocket frame payloads, it may be possible to bypass the usual size limits on memory use. Impact If a web application has WebSocket endpoints, it may be possible for an attacker to execute a DoS attack through excessive memory use(CVE-2026-54274)

If an application makes multiple requests to the same domain, but with different per-request server_hostname parameters, then the later calls may succeed by reusing the existing connection when they should have been rejected due to the TLS SNI check.(CVE-2026-54275)

If the client follows a redirect (the default option) to an attacker controlled domain, the attacker may be able to extract the auth digest.

This likely requires an open redirect vulnerability or similar on the target domain for an attacker to be able to execute. Further, the attacker is only receiving the digest, so should only be able to extract the user's credentials if the cryptography is weak or there is some kind of password reuse.(CVE-2026-54276)

It is possible to bypass the max_line_size check in parts of an HTTP request in the C parser. Impact If using the optimized C parser (the default in pre-built wheels), then an attacker may be able to send oversized lines through the HTTP parser and use an excessive amount of memory, potentially leading to DoS.(CVE-2026-54277)

An attacker may be able to send a compressed payload in specific situations that could be decompressed into memory, potentially leading to DoS (a zip bomb edge case).(CVE-2026-54278)

Host-only cookies If you save a cookie and later restore it, you lose the host-only status. CookieJar.save()CookieJar.load() affects host-only cookies loaded from disk that may be sent to subdomains that should previously have been banned(CVE-2026-54279)

Payload resources are not closed correctly when a client disconnects in the middle of a write. Impact If a payload is using an open file or similar limited resource, then an attacker may be able to cause resource starvation temporarily until garbage collection or similar closes the file.(CVE-2026-54280)

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, if an attacker sends large incomplete websocket frame payloads, it may be possible to bypass the usual size limits on memory use. This vulnerability is fixed in 3.14.1.

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, if an attacker sends large incomplete websocket frame payloads, it may be possible to bypass the usual size limits on memory use. This vulnerability is fixed in 3.14.1.

TuxCare rebuilt aiohttp to address 6 CVEs. Fixed in 3.8.6.post7+tuxcare.

TuxCare rebuilt aiohttp to address 5 CVEs. Fixed in 3.8.5.post18+tuxcare.

TuxCare rebuilt aiohttp to address 5 CVEs. Fixed in 3.8.4.post14+tuxcare.

TuxCare rebuilt aiohttp to address 7 CVEs. Fixed in 3.8.1.post16+tuxcare.

This update for python-aiohttp fixes the following issues

• CVE-2026-50269: improper validation of user-controlled strings allows for CRLF injection in multipart headers (bsc#1268398).
• CVE-2026-54273: no limit in the HTTP/1 pipelined request queue can lead to excessive resource consumption (bsc#1268543).
• CVE-2026-54274: incomplete websocket frame payloads can bypass memory use limits and cause a DoS via excessive resource consumption (bsc#1268544).
• CVE-2026-54275: server_hostname TLS SNI check bypass when an existing connection is reused (bsc#1268549).
• CVE-2026-54277: max_line_size bypass when using the optimised C HTTP parser can lead to excessive resource consumption (bsc#1268556).
• CVE-2026-54278: unread compressed request bodies can bypass client_max_size during cleanup and cause a DoS (bsc#1268559).
• CVE-2026-54279: host-only cookies become domain cookies after CookieJar persistence (bsc#1268560).
• CVE-2026-54280: payload resources are not closed correctly when a client disconnects in the middle of a write and can cause resource starvation (bsc#1268561).

Root has patched CVE-2026-54274 in the aiohttp package for Root:PyPI. Multiple fixed versions available.

This update for python-aiohttp fixes the following issues

• CVE-2026-50269: improper validation of user-controlled strings allows for CRLF injection in multipart headers (bsc#1268398).
• CVE-2026-54273: no limit in the HTTP/1 pipelined request queue can lead to excessive resource consumption (bsc#1268543).
• CVE-2026-54274: incomplete websocket frame payloads can bypass memory use limits and cause a DoS via excessive resource consumption (bsc#1268544).
• CVE-2026-54275: server_hostname TLS SNI check bypass when an existing connection is reused (bsc#1268549).
• CVE-2026-54277: max_line_size bypass when using the optimised C HTTP parser can lead to excessive resource consumption (bsc#1268556).
• CVE-2026-54278: unread compressed request bodies can bypass client_max_size during cleanup and cause a DoS (bsc#1268559).
• CVE-2026-54279: host-only cookies become domain cookies after CookieJar persistence (bsc#1268560).
• CVE-2026-54280: payload resources are not closed correctly when a client disconnects in the middle of a write and can cause resource starvation (bsc#1268561).

This update for python-aiohttp fixes the following issues

• CVE-2026-22815: insufficient restrictions in header/trailer handling can cause uncapped memory usage and a denial of service (bsc#1261320).
• CVE-2026-34513: unbounded DNS cache can cause a excessive memory usage and lead to a denial of service (bsc#1261321).
• CVE-2026-34514: content_type parameter manipulation can lead to header injection (bsc#1261322).
• CVE-2026-34516: response with excessive multipart headers can use more memory than intended and cause a denial of service (bsc#1261329).
• CVE-2026-34517: large multipart form fields read into memory without size check can cause a denial of service (bsc#1261331).
• CVE-2026-34518: retained Cookie and Proxy-Authorization headers when following redirects can lead to information disclosure (bsc#1261332).
• CVE-2026-34519: response reason parameter can be use to perform header injection (bsc#1261334).
• CVE-2026-34520: improper character handling by C parser can lead to header injection (bsc#1261335).
• CVE-2026-34525: multiple Host headers allow for potential security bypass in proxy servers (bsc#1261343).
• CVE-2026-34993: loading untrusted input in CookieJar.load() can lead to arbitrary code execution (bsc#1267471).
• CVE-2026-47265: cookies set with the cookies parameter on requests are sent after following a cross-origin redirect and can leak sensitive data (bsc#1267561).
• CVE-2026-50269: improper validation of user-controlled strings allows for CRLF injection in multipart headers (bsc#1268398).
• CVE-2026-54273: no limit in the HTTP/1 pipelined request queue can lead to excessive resource consumption (bsc#1268543).
• CVE-2026-54274: incomplete websocket frame payloads can bypass memory use limits and cause a DoS via excessive resource consumption (bsc#1268544).
• CVE-2026-54275: server_hostname TLS SNI check bypass when an existing connection is reused (bsc#1268549).
• CVE-2026-54277: max_line_size bypass when using the optimised C HTTP parser can lead to excessive resource consumption (bsc#1268556).
• CVE-2026-54278: unread compressed request bodies can bypass client_max_size during cleanup and cause a DoS (bsc#1268559).
• CVE-2026-54279: host-only cookies become domain cookies after CookieJar persistence (bsc#1268560).
• CVE-2026-54280: payload resources are not closed correctly when a client disconnects in the middle of a write and can cause resource starvation (bsc#1268561).

This update for python-aiohttp fixes the following issues:

• CVE-2026-50269: improper validation of user-controlled strings allows for CRLF injection in multipart headers (bsc#1268398).
• CVE-2026-54273: no limit in the HTTP/1 pipelined request queue can lead to excessive resource consumption (bsc#1268543).
• CVE-2026-54274: incomplete websocket frame payloads can bypass memory use limits and cause a DoS via excessive resource consumption (bsc#1268544).
• CVE-2026-54275: server_hostname TLS SNI check bypass when an existing connection is reused (bsc#1268549).
• CVE-2026-54277: max_line_size bypass when using the optimised C HTTP parser can lead to excessive resource consumption (bsc#1268556).
• CVE-2026-54278: unread compressed request bodies can bypass client_max_size during cleanup and cause a DoS (bsc#1268559).
• CVE-2026-54279: host-only cookies become domain cookies after CookieJar persistence (bsc#1268560).
• CVE-2026-54280: payload resources are not closed correctly when a client disconnects in the middle of a write and can cause resource starvation (bsc#1268561).