CVE-2026-91766: php_group php
Vulnerability summary
CVE-2026-91766 is a medium (CVSS 5.9) vulnerability in php_group php. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 25.7% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 9 · Related 6Timeline
- 25-09-2026PublishedVulnerability first disclosed.
- 28-09-2026Last modifiedVulnerability information updated.
Description
When the http:// stream wrapper follows a redirect it forwards the user-supplied Authorization, Cookie and Proxy-Authorization headers unchanged, even when the redirect target is a different host, a different port, or a downgrade from HTTPS to HTTP. A server that can steer a redirect therefore receives credentials that were only meant for the original origin. This is the same class of issue that libcurl fixed in 7.58.0 ( CVE-2018-1000007 https://github.com/advisories/GHSA-g7x2-hrfp-pv5f ).
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- OSV · DebianEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- NVDNIST5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS trend
Probability
0.34%
Chance of exploitation in the next 30 days
Percentile
26%
Versus all other CVEs
30-day change
Change unavailable
Change unavailable
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-200Exposure of Sensitive Information to an Unauthorized ActorThe product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
- CWE-522Insufficiently Protected CredentialsThe product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.
Affected systems
Ubuntu7 products
- php5All versions (No fix recorded)
- php7.0All versions (No fix recorded)
- php7.2All versions (No fix recorded)
- php7.4All versions (No fix recorded)
- php8.1All versions (No fix recorded)
Debian2 products
- php8.2< 8.2.34-1~deb12u1
- php8.4< 8.4.26-1~deb13u1 | < 8.4.26-1
Php_group1 product
- php≥ 8.2.*, < 8.2.34 | ≥ 8.3.*, < 8.3.35 | ≥ 8.4.*, < 8.4.26 | ≥ 8.5.*, < 8.5.11
3 vendors · 10 products