CVE-2026-39243

MEDIUMPre-NVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-07-10. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 4 sources updated this weekElevated
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: Elevated riskExposed: 0

A fix is available — apply it.

decompress before 4.2.2 allows arbitrary hardlink creation during archive extraction, enabling file read disclosure and file corruption. When processing hardlink entries (type === 'link'), the x.linkname field from the archive is passed directly to fs.link() without validation (index.js line 113). An attacker can craft an archive with a hardlink entry whose linkname is an absolute path to any file on the same filesystem. This creates a hardlink inside the extraction directory that shares the same inode as the target file, enabling both reading and overwriting the original file's content. Hardlinks are limited to files on the same filesystem and cannot target directories.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
41(Track)
EG Risk 41/100SSVC: 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
Severity55% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
23%
KEV
Not listed

Published

July 9, 2026

Last Modified

July 13, 2026

Advisory Details (2)

Auto-updated Jul 10, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

[CVE-2026-39243] Arbitrary hardlink creation during extraction → file read disclosure & corruption · Issue #113 · kevva/decompress · GitHub

https://github.com/kevva/decompress/issues/113
generic

GitHub - kevva/decompress: Extracting archives made easy · GitHub

https://github.com/kevva/decompress

Vendor Advisories for CVE-2026-39243(2)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatdotnet8-0-main-8.0.128-1.1.hum12026-07-10redhat
npmdecompress—ghsa

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

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
decompress———

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 17× in last 7d / 68× 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 196 total refreshes for this CVE.

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

Related CVEs(same product + same vendor + same CWE)

Same product

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npm:decompress

Frequently asked(5)

What is CVE-2026-39243?
CVE-2026-39243 is a medium vulnerability published on July 9, 2026. decompress before 4.2.2 allows arbitrary hardlink creation during archive extraction, enabling file read disclosure and file corruption. When processing hardlink entries (type === 'link'), the x.linkname field from the archive is passed directly to fs.link() without validation (index.js line 113).…
When was CVE-2026-39243 disclosed?
CVE-2026-39243 was first published in the National Vulnerability Database on July 9, 2026, with the most recent update on July 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-39243 actively exploited?
CVE-2026-39243 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 77.0% of all scored CVEs.
What is the CVSS score of CVE-2026-39243?
CVE-2026-39243 has a CVSS v3.1 base score of 5.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-39243?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-39243, 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

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