CVE-2026-46644

MEDIUMPre-NVD 6.96.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 57% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
6.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 6.9Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
6.9
EG Score
6.9(medium)
EG Risk
46(Track)
EG Risk 46/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity69% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
43%
KEV
Not listed

Published

May 28, 2026

Last Modified

July 15, 2026

Advisory Details (3)

Auto-updated Jul 15, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github Patch Available🟡 PoC Available

symfony/polyfill-intl-idn accepts xn-- labels whose Punycode payload decodes to ASCII-only: insecure equivalence · Advisory · symfony/polyfill · GitHub

https://github.com/symfony/polyfill/security/advisories/GHSA-2xf4-cg6j-vhgq
github_release Patch Available

v1.38.1

Patch available: symfony/polyfill v1.38.1

https://github.com/symfony/polyfill/releases/tag/v1.38.1
github_commit Patch Available

commit 1be936e2491c (symfony/polyfill)

Patch available: symfony/polyfill v1.38.1 (contains commit 1be936e2491c)

https://github.com/symfony/polyfill/commit/1be936e2491ccebe152bd736dfc91eb1422c8bec

Vendor Advisories for CVE-2026-46644(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(5 across 4 ecosystems)
Packagist(2)
PackageVulnerable rangeFixed inDependents
symfony/polyfillv1.17.1 ... v1.38.0 (24 versions)1.38.1—
symfony/polyfill-intl-idnv1.17.1 ... v1.37.0 (22 versions)1.38.1—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
php-symfony-polyfill1.22.1-1 ... 1.41.0-2 (39 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
php-symfony-polyfill1.27.0-2 ... 1.41.0-2 (25 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
php-symfony-polyfill1.1.0-1 ... 1.9.0-1 (54 versions)1.38.1-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 5× in last 7d / 39× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-04 05:06 UTCEPSS rescore
  2. 2026-09-02 14:12 UTCEPSS rescore
  3. 2026-09-01 13:54 UTCEPSS rescore
  4. 2026-08-30 19:17 UTCEPSS rescore
  5. 2026-08-30 01:22 UTCEPSS rescore
  6. 2026-08-28 21:41 UTCEPSS rescore
  7. 2026-08-27 14:25 UTCEPSS rescore
  8. 2026-08-26 14:46 UTCEPSS rescore
  9. 2026-08-25 13:49 UTCEPSS rescore
  10. 2026-08-25 04:37 UTCEG score recompute
  11. 2026-08-23 14:26 UTCEG score recompute
  12. 2026-08-23 00:19 UTCEPSS rescore
  13. 2026-08-21 23:49 UTCEPSS rescore
  14. 2026-08-21 15:23 UTCEG score recompute
  15. 2026-08-20 22:55 UTCEPSS rescore
  16. 2026-08-20 10:42 UTCEG score recompute
  17. 2026-08-19 17:04 UTCEPSS rescore
  18. 2026-08-18 13:48 UTCEPSS rescore
  19. 2026-08-17 13:47 UTCEPSS rescore
  20. 2026-08-17 07:17 UTCEG score recompute
  21. 2026-08-16 14:56 UTCEPSS rescore
  22. 2026-08-16 02:32 UTCEG score recompute
  23. 2026-08-16 02:14 UTCEPSS rescore
  24. 2026-08-15 03:35 UTCEG score recompute
  25. 2026-08-15 01:30 UTCEPSS rescore
Show 48 more
  1. 2026-08-14 05:48 UTCEG score recompute
  2. 2026-08-13 22:00 UTCEPSS rescore
  3. 2026-08-13 08:02 UTCEG score recompute
  4. 2026-08-12 13:51 UTCEPSS rescore
  5. 2026-08-12 09:30 UTCEG score recompute
  6. 2026-08-11 11:43 UTCEG score recompute
  7. 2026-08-11 00:00 UTCEPSS rescore
  8. 2026-08-09 16:02 UTCEG score recompute
  9. 2026-08-09 13:46 UTCEPSS rescore
  10. 2026-08-08 18:16 UTCEG score recompute
  11. 2026-08-08 16:37 UTCEPSS rescore
  12. 2026-08-07 16:56 UTCEG score recompute
  13. 2026-08-06 19:09 UTCEG score recompute
  14. 2026-08-06 13:47 UTCEPSS rescore
  15. 2026-08-05 21:23 UTCEG score recompute
  16. 2026-08-05 19:17 UTCEPSS rescore
  17. 2026-08-04 23:37 UTCEG score recompute
  18. 2026-08-04 15:10 UTCEPSS rescore
  19. 2026-08-04 10:39 UTCEPSS rescore
  20. 2026-08-02 12:10 UTCEG score recompute
  21. 2026-08-02 02:27 UTCEPSS rescore
  22. 2026-08-01 14:23 UTCEG score recompute
  23. 2026-08-01 04:16 UTCEPSS rescore
  24. 2026-07-31 06:17 UTCEG score recompute
  25. 2026-07-30 16:28 UTCEPSS rescore
  26. 2026-07-30 01:30 UTCEPSS rescore
  27. 2026-07-29 12:27 UTCEG score recompute
  28. 2026-07-28 15:36 UTCEPSS rescore
  29. 2026-07-27 14:13 UTCEPSS rescore
  30. 2026-07-27 09:34 UTCEG score recompute
  31. 2026-07-26 14:54 UTCEPSS rescore
  32. 2026-07-26 14:54 UTCEPSS rescore
  33. 2026-07-25 14:18 UTCEPSS rescore
  34. 2026-07-24 14:17 UTCEPSS rescore
  35. 2026-07-23 03:17 UTCEG score recompute
  36. 2026-07-22 14:08 UTCEPSS rescore
  37. 2026-07-21 15:24 UTCEPSS rescore
  38. 2026-07-20 17:08 UTCEPSS rescore
  39. 2026-07-19 02:29 UTCEPSS rescore
  40. 2026-07-18 10:04 UTCEPSS rescore
  41. 2026-07-16 17:03 UTCEPSS rescore
  42. 2026-07-15 16:57 UTCEPSS rescore
  43. 2026-07-14 21:16 UTCEG score recompute▲ 6.90
  44. 2026-07-14 21:15 UTCMITRE cvelistV5CVSS v3 → 6.9 · CVSS v4 → 6.9 · severity → MEDIUM
  45. 2026-06-14 23:18 UTCEPSS rescore
  46. 2026-06-13 23:00 UTCEPSS rescore
  47. 2026-06-12 23:12 UTCEPSS rescore
  48. 2026-05-28 20:06 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-46644?
CVE-2026-46644 is a medium vulnerability published on May 28, 2026. 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…
When was CVE-2026-46644 disclosed?
CVE-2026-46644 was first published in the National Vulnerability Database on May 28, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-46644 actively exploited?
CVE-2026-46644 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 56.7% of all scored CVEs.
What is the CVSS score of CVE-2026-46644?
CVE-2026-46644 has a CVSS v3 base score of 6.9 (NVD).
How do I remediate CVE-2026-46644?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-46644, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-46644

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