Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Webhookd versions before 1.22.0 forward all incoming HTTP headers to webhook scripts as shell variables when Basic Auth (htpasswd) middleware is not configured. An attacker who can reach the service through a reverse proxy that does not strip client-supplied authentication headers can send a forged header such as X-WebAuthn-User, which a script may trust to impersonate another user. Upgrade to webhookd 1.22.0 or later, which restricts forwarded headers to an allowlist set by WHD_ALLOWED_UPSTREAM_HEADERS; add any upstream authentication headers you rely on to that setting.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 6.5 | Medium | 3.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0060, the 48th percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:13 UTC First seen by agentprime
- 31 Oct 2026, 14:13 UTC Confirmed by OSV