CVE-2026-56391

MEDIUMNVD 6.16.1—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.1 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 97% 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 — 5 sources updated this week
6.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.1Exploit: None knownExposed: 0

A fix is available — apply it.

GNU coreutils uniq is vulnerable to an out‑of‑bounds read due to incorrect handling of multibyte input when the -w (--check-chars) option is used. The find_field() function miscalculates the byte length of characters by repeatedly processing a fixed pointer instead of advancing through the input, resulting in an inflated length value. This incorrect length is later used in a memcmp operation, causing reads beyond the allocated buffer when processing crafted multibyte input.

When running GNU coreutils uniq with attacker-provided arguments, this behavior leads to a crash and potential adjacent heap memory exposure.

This issue has been fixed in the commit d64e35a8a4c0e4608321433e0d84d917e4e36371.

CVSS v3
6.1
EG Score
6.1(medium)
EG Risk
28(Track)
EG Risk 28/100SSVC: 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
Severity61% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

July 24, 2026

Last Modified

August 26, 2026

Advisory Details (3)

Auto-updated Jul 24, 2026
No patch confirmed yet.
generic

uniq: fix read overrun with -w - coreutils.git - GNU coreutils

https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=d64e35a8a4c0e4608321433e0d84d917e4e36371
generic

coreutils.git - GNU coreutils

https://git.savannah.gnu.org/cgit/coreutils.git/
generic

Vulnerabilities in GNU coreutils software | CERT Polska

https://cert.pl/en/posts/2026/07/CVE-2026-56391

Vendor Advisories for CVE-2026-56391(2)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatcoreutils-main-9.11-5.1.hum12026-07-27redhat

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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
coreutils8.32-4 ... 9.7-3 (14 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
coreutils9.1-1 ... 9.7-3 (12 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
coreutils9.10-1, 9.7-3——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
coreutils9.10-1, 9.7-3——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 23× in last 7d / 104× 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 127 total refreshes for this CVE.

  1. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-30 00:21 UTCEG score recompute
  3. 2026-08-30 00:21 UTCVendor advisory
  4. 2026-08-30 00:21 UTCGHSA enrichment
  5. 2026-08-28 21:42 UTCEPSS rescore
  6. 2026-08-27 21:07 UTCEG score recompute
  7. 2026-08-27 21:07 UTCVendor advisory
  8. 2026-08-27 21:07 UTCGHSA enrichment
  9. 2026-08-27 14:25 UTCEPSS rescore
  10. 2026-08-26 16:20 UTCEG score recompute▲ 1.50
  11. 2026-08-26 16:20 UTCVendor advisory
  12. 2026-08-26 16:20 UTCGHSA enrichment
  13. 2026-08-26 16:17 UTCNVD updateCVSS v3 → 6.1
  14. 2026-08-26 14:46 UTCEPSS rescore
  15. 2026-08-25 20:15 UTCEG score recompute
  16. 2026-08-25 20:15 UTCVendor advisory
  17. 2026-08-25 20:15 UTCGHSA enrichment
  18. 2026-08-25 13:49 UTCEPSS rescore
  19. 2026-08-24 18:07 UTCEG score recompute
  20. 2026-08-24 18:07 UTCVendor advisory
  21. 2026-08-24 18:07 UTCGHSA enrichment
  22. 2026-08-23 15:49 UTCVendor advisory
  23. 2026-08-23 15:49 UTCGHSA enrichment
  24. 2026-08-22 13:41 UTCEG score recompute
  25. 2026-08-22 13:41 UTCVendor advisory
Show 75 more
  1. 2026-08-22 13:41 UTCGHSA enrichment
  2. 2026-08-21 23:49 UTCEPSS rescore
  3. 2026-08-21 11:33 UTCEG score recompute
  4. 2026-08-21 11:33 UTCVendor advisory
  5. 2026-08-21 11:33 UTCGHSA enrichment
  6. 2026-08-20 22:55 UTCEPSS rescore
  7. 2026-08-20 09:25 UTCEG score recompute
  8. 2026-08-20 09:25 UTCVendor advisory
  9. 2026-08-20 09:25 UTCGHSA enrichment
  10. 2026-08-19 17:04 UTCEPSS rescore
  11. 2026-08-19 07:17 UTCEG score recompute
  12. 2026-08-19 07:17 UTCVendor advisory
  13. 2026-08-19 07:17 UTCGHSA enrichment
  14. 2026-08-18 13:48 UTCEPSS rescore
  15. 2026-08-18 05:06 UTCEG score recompute
  16. 2026-08-18 05:06 UTCVendor advisory
  17. 2026-08-18 05:06 UTCGHSA enrichment
  18. 2026-08-17 13:47 UTCEPSS rescore
  19. 2026-08-17 02:57 UTCEG score recompute
  20. 2026-08-17 02:57 UTCVendor advisory
  21. 2026-08-17 02:57 UTCGHSA enrichment
  22. 2026-08-16 14:56 UTCEPSS rescore
  23. 2026-08-16 02:14 UTCEPSS rescore
  24. 2026-08-16 00:49 UTCEG score recompute
  25. 2026-08-16 00:49 UTCVendor advisory
  26. 2026-08-16 00:49 UTCGHSA enrichment
  27. 2026-08-15 01:30 UTCEPSS rescore
  28. 2026-08-14 22:40 UTCEG score recompute
  29. 2026-08-14 22:40 UTCVendor advisory
  30. 2026-08-14 22:40 UTCGHSA enrichment
  31. 2026-08-13 22:00 UTCEPSS rescore
  32. 2026-08-13 20:32 UTCVendor advisory
  33. 2026-08-13 20:32 UTCGHSA enrichment
  34. 2026-08-12 18:24 UTCEG score recompute
  35. 2026-08-12 18:24 UTCVendor advisory
  36. 2026-08-12 18:24 UTCGHSA enrichment
  37. 2026-08-12 13:51 UTCEPSS rescore
  38. 2026-08-11 16:17 UTCEG score recompute
  39. 2026-08-11 16:17 UTCVendor advisory
  40. 2026-08-11 16:17 UTCGHSA enrichment
  41. 2026-08-11 00:00 UTCEPSS rescore
  42. 2026-08-10 14:08 UTCEG score recompute
  43. 2026-08-10 14:08 UTCVendor advisory
  44. 2026-08-10 14:08 UTCGHSA enrichment
  45. 2026-08-09 13:46 UTCEPSS rescore
  46. 2026-08-09 12:00 UTCEG score recompute
  47. 2026-08-09 12:00 UTCVendor advisory
  48. 2026-08-09 12:00 UTCGHSA enrichment
  49. 2026-08-08 16:37 UTCEPSS rescore
  50. 2026-08-08 09:51 UTCEG score recompute
  51. 2026-08-08 09:51 UTCVendor advisory
  52. 2026-08-08 09:51 UTCGHSA enrichment
  53. 2026-08-07 07:43 UTCEG score recompute
  54. 2026-08-07 07:43 UTCVendor advisory
  55. 2026-08-07 07:43 UTCGHSA enrichment
  56. 2026-08-06 13:47 UTCEPSS rescore
  57. 2026-08-06 05:35 UTCEG score recompute
  58. 2026-08-06 05:35 UTCVendor advisory
  59. 2026-08-06 05:35 UTCGHSA enrichment
  60. 2026-08-05 19:17 UTCEPSS rescore
  61. 2026-08-05 03:27 UTCEG score recompute
  62. 2026-08-05 03:27 UTCVendor advisory
  63. 2026-08-05 03:27 UTCGHSA enrichment
  64. 2026-08-04 15:10 UTCEPSS rescore
  65. 2026-08-04 10:39 UTCEPSS rescore
  66. 2026-08-04 01:19 UTCEG score recompute
  67. 2026-08-04 01:19 UTCVendor advisory
  68. 2026-08-04 01:19 UTCGHSA enrichment
  69. 2026-08-03 10:36 UTCEPSS rescore
  70. 2026-08-02 23:11 UTCEG score recompute
  71. 2026-08-02 23:11 UTCVendor advisory
  72. 2026-08-02 23:11 UTCGHSA enrichment
  73. 2026-08-02 02:27 UTCEPSS rescore
  74. 2026-08-01 21:03 UTCEG score recompute
  75. 2026-08-01 21:03 UTCVendor advisory

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-56391?
CVE-2026-56391 is a medium vulnerability published on July 24, 2026. GNU coreutils uniq is vulnerable to an out‑of‑bounds read due to incorrect handling of multibyte input when the -w (--check-chars) option is used. The find_field() function miscalculates the byte length of characters by repeatedly processing a fixed pointer instead of advancing through the input,…
When was CVE-2026-56391 disclosed?
CVE-2026-56391 was first published in the National Vulnerability Database on July 24, 2026, with the most recent update on August 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56391 actively exploited?
CVE-2026-56391 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 97.0% of all scored CVEs.
What is the CVSS score of CVE-2026-56391?
CVE-2026-56391 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-56391?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56391, 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.

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