CVE-2026-26824

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2026-06-03. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 3 sources updated this weekElevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: Elevated riskExposed: 0

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

libxls through version 1.6.3 contains a use of uninitialized memory vulnerability in the OLE container parser. Memory allocated for the Master Sector Allocation Table (MSAT) in read_MSAT() is not fully initialized before being consumed by ole2_validate_sector_chain(), which may result in application crashes or potential information disclosure when processing a crafted XLS file

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
60(Attend)
EG Risk 60/100SSVC: Attend

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
Severity65% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
14%
KEV
Not listed

Published

June 3, 2026

Last Modified

July 22, 2026

Advisory Details (1)

Auto-updated Jun 12, 2026
No patch confirmed yet.
generic

Use of uninitialized memory in libxls OLE sector chain validation · Issue #155 · libxls/libxls · GitHub

https://github.com/libxls/libxls/issues/155

Vendor Advisories for CVE-2026-26824(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 62× 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 121 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-26824?
CVE-2026-26824 is a medium vulnerability published on June 3, 2026. libxls through version 1.6.3 contains a use of uninitialized memory vulnerability in the OLE container parser. Memory allocated for the Master Sector Allocation Table (MSAT) in readMSAT() is not fully initialized before being consumed by ole2validatesectorchain(), which may result in application…
When was CVE-2026-26824 disclosed?
CVE-2026-26824 was first published in the National Vulnerability Database on June 3, 2026, with the most recent update on July 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-26824 actively exploited?
CVE-2026-26824 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 86.3% of all scored CVEs.
What is the CVSS score of CVE-2026-26824?
CVE-2026-26824 has a CVSS v3.1 base score of 6.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-26824?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-26824, 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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