CVE-2026-45623

CRITICALNVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit probability: 0.6%, top 53% 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, nvd
Trending — 3 sources updated this week
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.1Exploit: None knownExposed: 0

A fix is available — apply it.

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. In versions 8.5.11 and prior, the PreviousMap parses the /*# sourceMappingURL=PATH */ comment from any CSS string passed to process() and dereferences PATH against the local filesystem with no scheme, allowlist, or traversal check. An attacker who controls the CSS input can cause the host process to read any file readable by Node and leak the first ~10 bytes of its content through the resulting JSON.parse SyntaxError message. The bug also yields a precise file-existence oracle and a controllable-read primitive that may be combined with large-file targets for DoS. The behaviour is triggered with PostCSS's default options — no from, no map, no plugins required — and is therefore reachable from any pipeline that runs untrusted CSS through PostCSS (CMS themes, user-uploaded styles, browser-extension/userstyle processors, build pipelines for third-party packages, blog comment renderers, etc.). This issue has been fixed in version 8.5.12.

CVSS v3
9.1
EG Score
9.1(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
Severity91% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
47%
KEV
Not listed

Published

July 23, 2026

Last Modified

August 7, 2026

Advisory Details (1)

Auto-updated Sep 16, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Arbitrary file read and information disclosure via attacker-controlled sourceMappingURL in CSS comments · Advisory · postcss/postcss · GitHub

https://github.com/postcss/postcss/security/advisories/GHSA-6g55-p6wh-862q

Vendor Advisories for CVE-2026-45623(20)

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

Patch Availability(28)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatopenshift4/ose-console-rhel9:17883115202026-09-09redhat
redhatrhoai/odh-mod-arch-model-registry-rhel9:17883121572026-09-08redhat
redhatopenshift4/ose-console-rhel9:17883599342026-09-08redhat
redhatopenshift4/ose-console-rhel9:17883509632026-09-08redhat
redhatsatellite/iop-host-inventory-frontend-rhel9:17882609412026-09-03redhat
redhatsatellite/iop-host-inventory-frontend-rhel9:17883222432026-09-03redhat
redhatopenshift4/ose-console-rhel9:17877463822026-09-01redhat
redhatdevspaces/openvsx-rhel9:17877591452026-09-01redhat
redhatdiscovery/discovery-ui-rhel9:17882061962026-08-31redhat
redhatrhoai/odh-mod-arch-model-registry-rhel9:17872506172026-08-27redhat
redhatrhacm2/console-rhel9:17873351052026-08-26redhat
redhatrhacm2/console-rhel9:17876870622026-08-26redhat
redhatrhacm2/console-rhel9:17873392482026-08-26redhat
redhatrhacm2/console-rhel9:17873392492026-08-26redhat
redhatopenshift-service-mesh/kiali-rhel9:17870764952026-08-25redhat
redhatopenshift-service-mesh/kiali-rhel9:17871656832026-08-25redhat
redhatmulticluster-engine/console-mce-rhel9:17872590482026-08-25redhat
redhatmulticluster-engine/console-mce-rhel9:17870793592026-08-25redhat
redhatopenshift-service-mesh/kiali-rhel9:17870921982026-08-25redhat
redhatmulticluster-engine/console-mce-rhel9:17866688562026-08-25redhat
redhatopenshift-service-mesh/kiali-rhel9:17870922552026-08-25redhat
redhatopenshift-service-mesh/kiali-rhel9:17870771082026-08-25redhat
redhatrh-podman-desktop-0:1.1.2-1.el10_22026-08-20redhat
redhatmulticluster-engine/console-mce-rhel9:17869119772026-08-19redhat
redhatrhacm2/console-rhel9:17869083612026-08-19redhat
redhatansible-automation-platform/automation-portal:17870471882026-08-18redhat
redhatansible-automation-platform/automation-portal:17870471142026-08-18redhat
redhatrhacm2/console-rhel9:17865477712026-08-12redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
node-postcss8.2.1+~cs5.3.23-8 ... 8.5.9+~cs9.3.30-1 (31 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
node-postcss8.4.20+~cs8.0.23-1 ... 8.5.9+~cs9.3.30-1 (18 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
node-postcss8.4.49+~cs9.2.32-1 ... 8.5.9+~cs9.3.30-1 (14 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
node-postcss8.4.49+~cs9.2.32-1, 8.5.6+~cs9.3.28-1, 8.5.8+~cs9.3.30-1, 8.5.9+~cs9.3.30-18.5.12+~cs9.3.32-1—
npm(1)
PackageVulnerable rangeFixed inDependents
postcss—8.5.12—

Weakness Classification(2)

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

Additional Vendor Advisories

(8)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 33× in last 7d / 143× 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.

Showing the most recent 100 of 229 total refreshes for this CVE.

  1. 2026-09-18 22:34 UTCEG score recompute
  2. 2026-09-18 22:34 UTCVendor advisory
  3. 2026-09-18 19:28 UTCEPSS rescore
  4. 2026-09-18 11:17 UTCVendor advisory
  5. 2026-09-18 07:12 UTCVendor advisory
  6. 2026-09-18 03:06 UTCEG score recompute
  7. 2026-09-18 03:06 UTCVendor advisory
  8. 2026-09-17 19:31 UTCEPSS rescore
  9. 2026-09-17 09:17 UTCVendor advisory
  10. 2026-09-17 02:02 UTCEG score recompute
  11. 2026-09-17 02:02 UTCVendor advisory
  12. 2026-09-16 14:08 UTCEPSS rescore
  13. 2026-09-16 12:00 UTCVendor advisory
  14. 2026-09-16 06:46 UTCEG score recompute
  15. 2026-09-16 06:46 UTCVendor advisory
  16. 2026-09-16 05:15 UTCEPSS rescore
  17. 2026-09-14 16:14 UTCVendor advisory
  18. 2026-09-14 10:44 UTCVendor advisory
  19. 2026-09-14 06:33 UTCVendor advisory
  20. 2026-09-14 02:28 UTCVendor advisory
  21. 2026-09-13 22:22 UTCEG score recompute
  22. 2026-09-13 22:22 UTCVendor advisory
  23. 2026-09-13 16:47 UTCEPSS rescore
  24. 2026-09-13 15:28 UTCVendor advisory
  25. 2026-09-13 11:13 UTCVendor advisory
Show 75 more
  1. 2026-09-13 06:32 UTCVendor advisory
  2. 2026-09-13 02:26 UTCVendor advisory
  3. 2026-09-12 22:19 UTCVendor advisory
  4. 2026-09-12 17:42 UTCEG score recompute
  5. 2026-09-12 17:42 UTCVendor advisory
  6. 2026-09-12 15:01 UTCEPSS rescore
  7. 2026-09-12 13:22 UTCVendor advisory
  8. 2026-09-12 09:16 UTCVendor advisory
  9. 2026-09-12 05:11 UTCVendor advisory
  10. 2026-09-12 01:00 UTCVendor advisory
  11. 2026-09-11 20:55 UTCVendor advisory
  12. 2026-09-11 16:45 UTCEG score recompute
  13. 2026-09-11 16:45 UTCVendor advisory
  14. 2026-09-11 14:53 UTCEPSS rescore
  15. 2026-09-11 09:37 UTCEPSS rescore
  16. 2026-09-11 07:17 UTCVendor advisory
  17. 2026-09-11 03:09 UTCVendor advisory
  18. 2026-09-10 20:56 UTCVendor advisory
  19. 2026-09-10 15:10 UTCEG score recompute
  20. 2026-09-10 15:10 UTCVendor advisory
  21. 2026-09-10 09:34 UTCEPSS rescore
  22. 2026-09-09 08:56 UTCEG score recompute
  23. 2026-09-09 08:56 UTCVendor advisory
  24. 2026-09-08 22:00 UTCEPSS rescore
  25. 2026-09-08 01:36 UTCVendor advisory
  26. 2026-09-07 21:30 UTCEG score recompute
  27. 2026-09-07 21:30 UTCVendor advisory
  28. 2026-09-07 16:01 UTCEPSS rescore
  29. 2026-09-06 16:49 UTCEG score recompute
  30. 2026-09-06 16:49 UTCVendor advisory
  31. 2026-09-06 13:47 UTCEPSS rescore
  32. 2026-09-06 12:42 UTCVendor advisory
  33. 2026-09-06 08:30 UTCVendor advisory
  34. 2026-09-06 03:39 UTCVendor advisory
  35. 2026-09-05 23:33 UTCVendor advisory
  36. 2026-09-05 19:28 UTCEG score recompute
  37. 2026-09-05 19:28 UTCVendor advisory
  38. 2026-09-05 06:58 UTCVendor advisory
  39. 2026-09-04 17:37 UTCEG score recompute
  40. 2026-09-04 17:37 UTCVendor advisory
  41. 2026-09-04 13:16 UTCEG score recompute
  42. 2026-09-04 13:16 UTCVendor advisory
  43. 2026-09-04 05:06 UTCEPSS rescore
  44. 2026-09-02 14:12 UTCEPSS rescore
  45. 2026-09-01 23:22 UTCEG score recompute
  46. 2026-09-01 23:22 UTCVendor advisory
  47. 2026-09-01 13:54 UTCEPSS rescore
  48. 2026-08-31 05:16 UTCVendor advisory
  49. 2026-08-31 01:11 UTCVendor advisory
  50. 2026-08-30 21:06 UTCEG score recompute
  51. 2026-08-30 21:06 UTCVendor advisory
  52. 2026-08-30 19:17 UTCEPSS rescore
  53. 2026-08-30 17:00 UTCVendor advisory
  54. 2026-08-30 12:55 UTCVendor advisory
  55. 2026-08-30 08:44 UTCVendor advisory
  56. 2026-08-30 04:39 UTCEG score recompute
  57. 2026-08-30 04:39 UTCVendor advisory
  58. 2026-08-30 01:22 UTCEPSS rescore
  59. 2026-08-30 00:33 UTCEG score recompute
  60. 2026-08-30 00:33 UTCVendor advisory
  61. 2026-08-28 21:41 UTCEPSS rescore
  62. 2026-08-28 01:29 UTCVendor advisory
  63. 2026-08-27 21:08 UTCEG score recompute
  64. 2026-08-27 21:08 UTCVendor advisory
  65. 2026-08-27 14:25 UTCEPSS rescore
  66. 2026-08-27 14:15 UTCVendor advisory
  67. 2026-08-27 10:10 UTCVendor advisory
  68. 2026-08-27 04:20 UTCVendor advisory
  69. 2026-08-27 00:00 UTCVendor advisory
  70. 2026-08-26 19:54 UTCEG score recompute
  71. 2026-08-26 19:54 UTCVendor advisory
  72. 2026-08-26 14:46 UTCEPSS rescore
  73. 2026-08-26 11:54 UTCVendor advisory
  74. 2026-08-26 07:49 UTCVendor advisory
  75. 2026-08-26 03:38 UTCVendor advisory

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-45623?
CVE-2026-45623 is a critical vulnerability published on July 23, 2026. PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. In versions 8.5.11 and prior, the PreviousMap parses the /# sourceMappingURL=PATH / comment from any CSS string passed to process() and dereferences PATH against the…
When was CVE-2026-45623 disclosed?
CVE-2026-45623 was first published in the National Vulnerability Database on July 23, 2026, with the most recent update on August 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45623 actively exploited?
CVE-2026-45623 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 53.3% of all scored CVEs.
What is the CVSS score of CVE-2026-45623?
CVE-2026-45623 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-45623?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45623, 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-2026-45623

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