CVE-2026-91766: PHP · Information Exposure
Affects PHPSource CVE Database V5
Mentioned vulnerabilities
Not known to be exploited · CVSS 5.9 Medium · fixed in 8.5.11 : update PHP when convenient.
Data as of 8 Nov 2026, 23:24 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 8.5.11, 8.4.26, 8.3.35 +1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 8 Nov 2026.
What to do
Upgrade PHP to 8.5.11, 8.4.26, 8.3.35 or 8.2.34.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| PHP GroupPHP | Affected
| Fixed in
|
| PHP GroupPHP | Affected
| Fixed in
|
| PHP GroupPHP | Affected
| Fixed in
|
| PHP GroupPHP | Affected
| Fixed in
|
AI-suggested
If you cannot patch yet, avoid relying on redirects that could cause sensitive headers to be forwarded to unintended hosts or downgrade protocols.
Description
CVE-2026-91766 is a medium severity vulnerability in PHP where the http:// stream wrapper forwards sensitive headers such as Authorization, Cookie, and Proxy-Authorization unchanged when following redirects. This occurs even if the redirect target is a different host, port, or downgrades from HTTPS to HTTP, potentially exposing credentials to unintended servers.