CVE-2026-48979PHP Standard Library: HTTP/2 server-side missing content-length validation enables request smuggling
- 7.5HighCVSS base score
- 0.27%Exploitation in 30 daysEPSS · top 81% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
PHP Standard Library (PSL) is set of APIs covering async, collections, networking, I/O, cryptography, terminal UI, etc. In versions 6.1.0, 6.1.1 and 6.2.0, the Psl\H2\ServerConnection does not validate that the total bytes received in DATA frames match the content-length header declared in the HEADERS frame, allowing request smuggling. This is in violation of RFC 9113 §8.1.1. A malicious client is able to send more DATA bytes than declared, smuggling additional content past application-level size limits and send fewer DATA bytes than declared and close the stream early, causing applications that trust the declared length to behave incorrectly. The vulnerability is only reachable for consumers using Psl\H2\ServerConnection directly to accept untrusted client traffic. Consumers of documented high-level PSL APIs are not affected. This issue has been fixed in versions 6.1.2 and 6.2.1.
Timeline
ID reserved
By GitHub_M
- 22 days later
· 22 days later
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
| NVDNVD · Awaiting Analysis | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 0.27% · top 81% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
php-standard-library · php-standard-library
- affected >= 6.1.0, < 6.1.2
- affected >= 6.2.0, < 6.2.1
php-standard-library · php-standard-library/h2
- affected >= 6.1.0, < 6.1.2
- affected >= 6.2.0, < 6.2.1
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Packagistphp-standard-library/h2GHSA-pw9p-jvrm-f7rm (opens in a new tab)
- Packagistphp-standard-library/php-standard-libraryGHSA-pw9p-jvrm-f7rm (opens in a new tab)
References
References3
- https://github.com/php-standard-library/php-standard-library/security/advisories/GHSA-pw9p-jvrm-f7rm (opens in a new tab)x_refsource_CONFIRM
- https://github.com/php-standard-library/php-standard-library/releases/tag/6.1.2 (opens in a new tab)x_refsource_MISC
- https://github.com/php-standard-library/php-standard-library/releases/tag/6.2.1 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-37798 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-pw9p-jvrm-f7rm (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-48979)Record last updated .