🛡️ CVE-2026-46644 on Debian — php-symfony-polyfill
Description
Symfony Polyfill backports PHP features and provides compatibility layers for extensions and functions. From 1.17.1 until 1.38.1, symfony/polyfill-intl-idn accepts xn-- labels whose Punycode payload is empty or decodes to ASCII-only code points because Idn::process() does not enforce the UTS #46 revision 33 requirement that decoded ACE labels contain at least one non-ASCII code point. Originally unequal domain names can be regarded as equal, which can lead to blacklist bypassing, inconsistent URL parsing, and server-side request forgery in applications using the polyfill to canonicalise or compare hostnames. This issue is fixed in version 1.38.1.
Distribution advisory
This page covers CVE-2026-46644 as tracked by Debian, for the package php-symfony-polyfill. The fix is available in version 1.38.1-1; earlier versions remain affected.
How this vulnerability can be exploited
This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity low, availability none.
Weakness class
DEBIAN-CVE-2026-46644 is classified as CWE-1289: Improper Validation of Unsafe Equivalence in Input. The product receives an input value that is used as a resource identifier or other type of reference, but it does not validate or incorrectly validates that the input is equivalent to a potentially-unsafe value.
Affected software
DEBIAN-CVE-2026-46644 is recorded against 1 package.
- php-symfony-polyfill (fixed in 1.38.1-1)
Timeline and source
Published on 14 July 2026 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.
References
CVE-2026-46644 on other distributions
Each distribution ships its own build and its own fixed version. Pick the one you run:
Details
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| php-symfony-polyfill | — | 1.38.1-1 |
References
Similar Threats
- Unknown UBUNTU-CVE-2026-46644
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