Answer in brief
CVE-2026-43972 records a Medium severity secret exfiltration vulnerability in gun_http2 has an Origin Validation Error vulnerability. The source record does not mark it as known exploited. 1 affected package is mapped in the feed.
Answer in brief
CVE-2026-43972 records a Medium severity secret exfiltration vulnerability in gun_http2 has an Origin Validation Error vulnerability. The source record does not mark it as known exploited. 1 affected package is mapped in the feed.
Update gun to 2.4.0 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanSecret Exfiltration describes the vulnerability class recorded for this advisory. The current record does not mark CVE-2026-43972 as known exploited; continue to monitor the source for status changes. The feed includes package mappings that can be checked against lockfiles and deployed manifests.
| Package | Affected range | Fixed version |
|---|---|---|
| gunerlang | >=2.0.0,<2.4.0 | 2.4.0 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
CVE-2026-43972 records a Medium severity secret exfiltration vulnerability in gun_http2 has an Origin Validation Error vulnerability. The source record does not mark it as known exploited. 1 affected package is mapped in the feed.
The source record does not mark it as known exploited.
Check lockfiles and deployed manifests for gun.
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate gun to 2.4.0 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanSecret Exfiltration describes the vulnerability class recorded for this advisory. The current record does not mark CVE-2026-43972 as known exploited; continue to monitor the source for status changes. The feed includes package mappings that can be checked against lockfiles and deployed manifests.
| Package | Affected range | Fixed version |
|---|---|---|
| gunerlang | >=2.0.0,<2.4.0 | 2.4.0 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
CVE-2026-43972 records a Medium severity secret exfiltration vulnerability in gun_http2 has an Origin Validation Error vulnerability. The source record does not mark it as known exploited. 1 affected package is mapped in the feed.
The source record does not mark it as known exploited.
Check lockfiles and deployed manifests for gun.
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardOrigin Validation Error vulnerability in ninenines gun (gun_http2 module) allows cross-origin cookie injection via unvalidated HTTP/2 PUSH_PROMISE authority. In gun_http2:push_promise_frame/7, the :authority pseudo-header from an incoming PUSH_PROMISE frame is stored verbatim into the promised stream record without checking that it matches the connection's origin. When gun_http2:headers_frame/9 later processes the response headers for the promised stream, it calls gun_cookies:set_cookie_header/7 with the unvalidated server-supplied authority before any status branching and before user code can act. This violates RFC 7540 §10.6 / RFC 9113 §8.4, which require receivers to treat as a protocol error any push for a resource the server is not authoritative for. A malicious or compromised HTTP/2 server can plant cookies scoped to arbitrary third-party domains into the client's shared cookie store. This enables session fixation attacks against those domains and, if the planted cookie overrides a legitimate session token, may result in account takeover. No user interaction beyond making a normal HTTP/2 request to the attacker-controlled server is required. This issue affects gun: from 2.0.0 before 2.4.0.
Origin Validation Error vulnerability in ninenines gun (gun_http2 module) allows cross-origin cookie injection via unvalidated HTTP/2 PUSH_PROMISE authority. In gun_http2:push_promise_frame/7, the :authority pseudo-header from an incoming PUSH_PROMISE frame is stored verbatim into the promised stream record without checking that it matches the connection's origin. When gun_http2:headers_frame/9 later processes the response headers for the promised stream, it calls gun_cookies:set_cookie_header/7 with the unvalidated server-supplied authority before any status branching and before user code can act. This violates RFC 7540 §10.6 / RFC 9113 §8.4, which require receivers to treat as a protocol error any push for a resource the server is not authoritative for. A malicious or compromised HTTP/2 server can plant cookies scoped to arbitrary third-party domains into the client's shared cookie store. This enables session fixation attacks against those domains and, if the planted cookie overrides a legitimate session token, may result in account takeover. No user interaction beyond making a normal HTTP/2 request to the attacker-controlled server is required. This issue affects gun: from 2.0.0 before 2.4.0.