CVE-2026-48979 json
PHP Standard Library: HTTP/2 server-side missing content-length validation enables request smuggling
published 2026-06-17 4 mo ago modified 2026-09-10 1 mo ago also GHSA-pw9p-jvrm-f7rm , EUVD-2026-37798
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 18%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- packagist php-standard-library/h2 6.1.2, 6.2.1
- packagist php-standard-library/php-standard-library 6.1.2, 6.2.1
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 4 mo ago
Exploit prediction
0.27% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
| GitHub | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| packagist | php-standard-library/h2 | >=6.1.0, <6.1.2 >=6.2.0, <6.2.1 |
6.1.2 6.2.1 |
| packagist | php-standard-library/php-standard-library | >=6.1.0, <6.1.2 >=6.2.0, <6.2.1 |
6.1.2 6.2.1 |
Affected products
- php-standard-library php-standard-library
- php-standard-library php-standard-library/h2
Classification
- Weakness
-
- CWE-444 Inconsistent Interpretation of HTTP Requests
References
-
github.com
/php-standard-library/php-standard-library/security/advisories/GHSA-pw9p-jvrm-f7rm
web
-
github.com
/php-standard-library/php-standard-library/releases/tag/6.1.2
web
-
github.com
/php-standard-library/php-standard-library/releases/tag/6.2.1
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-48979
advisory
-
github.com
/php-standard-library/php-standard-library
package
Sources
- CVE List CVE-2026-48979
- GitHub Advisory GHSA-pw9p-jvrm-f7rm
- NVD CVE-2026-48979
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