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 — 4 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.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
r-cran-readxl1.3.1-2 ... 1.5.0-1 (8 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
r-cran-readxl1.4.2-1, 1.4.3-1, 1.4.4-1, 1.4.5-1, 1.5.0-1——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
r-cran-readxl1.4.5-1, 1.5.0-1——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
r-cran-readxl1.4.5-1, 1.5.0-1——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 36× 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 211 total refreshes for this CVE.

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

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 86.4% 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.

Dependency Blast Radius

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