CVE-2026-6276
Description
Using libcurl, when a custom `Host:` header is first set for an HTTP request and a second request is subsequently done using the same *easy handle* but without the custom `Host:` header set, the second request would use stale information and pass on cookies meant for the first host in the second request. Leak them.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Windows Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Affected | — |
| sid | Fixed | 8.20.0~rc3-1 |
| forky | Fixed | 8.20.0~rc3-1 |
| bullseye | Affected | — |
| bookworm | Affected | — |
References
- https://curl.se/docs/CVE-2026-6276.html
- https://curl.se/docs/CVE-2026-6276.json
- https://hackerone.com/reports/3671818
- http://www.openwall.com/lists/oss-security/2026/04/29/13
- https://security-tracker.debian.org/tracker/CVE-2026-6276
- https://www.suse.com/security/cve/CVE-2026-6276.html
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-6276
CWEs
CWE-319
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.