CVE-2026-56391

MEDIUMNVD 6.16.1
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This medium-severity CVE scores 6.1 under NVD CVSS v3. EPSS exploit probability: 0.2% (5th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
6.1EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.1Exploit: None knownExposed services: Not assessed

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
6.1MEDIUMmedium confidence
EG Risk
28
EG Risk 28/100

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 (value × EchelonGraph’s weight)
Severity61% × 45%
The EG Score, 6.1 of 10.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
5th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 24, 2026

Last Modified

August 26, 2026

Advisory Details (3)

Auto-updated Jul 24, 2026
Patch available.
Web page

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

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

coreutils.git - GNU coreutils

https://git.savannah.gnu.org/cgit/coreutils.git/
Web page

Vulnerabilities in GNU coreutils software | CERT Polska

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

Patch Availability(3)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntugnu-coreutils (9.7-3ubuntu2.1) @ resolute2026-10-04ubuntu
redhatcoreutils-0:9.5-8.el10_2.12026-09-16redhat
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 rangeFix by version rangeDependents
coreutils8.32-4 ... 9.7-3 (14 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
coreutils9.1-1 ... 9.7-3 (12 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
coreutils9.10-1, 9.7-3
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
coreutils9.10-1, 9.7-3
  • every version on: no fix on record
—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

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 11× in last 7d / 60× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 224 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 124 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  3. 2026-10-12 15:54 UTCEG score recompute
  4. 2026-10-11 19:38 UTCEG score recompute
  5. 2026-10-11 16:53 UTCEG score recompute
  6. 2026-10-11 14:16 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  10. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  11. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  12. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  13. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  14. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  15. 2026-10-04 07:47 UTCEG score recompute
  16. 2026-10-04 07:47 UTCVendor advisory
  17. 2026-10-04 07:47 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  18. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  19. 2026-10-03 03:22 UTCEG score recompute
  20. 2026-10-03 03:22 UTCVendor advisory
  21. 2026-10-03 03:22 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  22. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  23. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  24. 2026-10-01 06:12 UTCEG score recompute
  25. 2026-10-01 06:12 UTCVendor advisory
Show 75 more
  1. 2026-10-01 06:12 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  2. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  3. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  4. 2026-09-28 05:02 UTCEG score recompute
  5. 2026-09-28 05:02 UTCVendor advisory
  6. 2026-09-28 05:02 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  7. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  8. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  9. 2026-09-25 10:17 UTCEG score recompute
  10. 2026-09-25 10:17 UTCVendor advisory
  11. 2026-09-25 10:17 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  12. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  13. 2026-09-24 01:11 UTCEG score recompute
  14. 2026-09-24 01:11 UTCVendor advisory
  15. 2026-09-24 01:11 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  16. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  17. 2026-09-22 22:37 UTCEG score recompute
  18. 2026-09-22 22:37 UTCVendor advisory
  19. 2026-09-22 22:37 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  20. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  21. 2026-09-20 01:44 UTCEG score recompute
  22. 2026-09-20 01:44 UTCVendor advisory
  23. 2026-09-20 01:44 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  24. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  25. 2026-09-18 03:02 UTCEG score recompute
  26. 2026-09-18 03:02 UTCVendor advisory
  27. 2026-09-18 03:02 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  28. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  29. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  30. 2026-09-16 11:59 UTCVendor advisory
  31. 2026-09-16 11:59 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  32. 2026-09-15 09:42 UTCEG score recompute
  33. 2026-09-15 09:42 UTCVendor advisory
  34. 2026-09-15 09:42 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  35. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  36. 2026-09-13 22:20 UTCEG score recompute
  37. 2026-09-13 22:20 UTCVendor advisory
  38. 2026-09-13 22:19 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  39. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  40. 2026-09-12 19:56 UTCEG score recompute
  41. 2026-09-12 19:56 UTCVendor advisory
  42. 2026-09-12 19:56 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  43. 2026-09-11 17:48 UTCEG score recompute
  44. 2026-09-11 17:48 UTCVendor advisory
  45. 2026-09-11 17:48 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  46. 2026-09-10 14:54 UTCEG score recompute
  47. 2026-09-10 14:54 UTCVendor advisory
  48. 2026-09-10 14:54 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  49. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  50. 2026-09-09 08:51 UTCEG score recompute
  51. 2026-09-09 08:51 UTCVendor advisory
  52. 2026-09-09 08:51 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  53. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  54. 2026-09-07 21:27 UTCEG score recompute
  55. 2026-09-07 21:27 UTCVendor advisory
  56. 2026-09-07 21:27 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  57. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  58. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  59. 2026-09-05 19:26 UTCEG score recompute
  60. 2026-09-05 19:26 UTCVendor advisory
  61. 2026-09-05 19:26 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  62. 2026-09-04 12:56 UTCVendor advisory
  63. 2026-09-04 12:56 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  64. 2026-09-01 23:19 UTCEG score recompute
  65. 2026-09-01 23:19 UTCVendor advisory
  66. 2026-09-01 23:19 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  67. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  68. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  69. 2026-08-31 02:30 UTCEG score recompute
  70. 2026-08-31 02:30 UTCVendor advisory
  71. 2026-08-31 02:30 UTCGHSA enrichmentGHSA-7xvj-m9x7-qgxq
  72. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  73. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  74. 2026-08-30 00:21 UTCEG score recompute
  75. 2026-08-30 00:21 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-56391?
CVE-2026-56391 is a medium-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-56391 published?
The CVE record for CVE-2026-56391 was published on July 24, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of August 26, 2026; the record at its source may have been updated since.
Is CVE-2026-56391 actively exploited?
CVE-2026-56391 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (5th percentile of EPSS-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?
A fix for CVE-2026-56391 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-56391 are linked in the Vendor Advisories panel on this page.

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