CVE-2026-2703

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.5 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 89% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
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: None knownExposed: 0

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

A weakness has been identified in xlnt-community xlnt up to 1.6.1. Impacted is the function xlnt::detail::decode_base64 of the file source/detail/cryptography/base64.cpp of the component Encrypted XLSX File Parser. Executing a manipulation can lead to off-by-one. The attack requires local access. The exploit has been made available to the public and could be used for attacks. This patch is called f2d7bf494e5c52706843cf7eb9892821bffb0734. Applying a patch is advised to resolve this issue.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
25(Track)
EG Risk 25/100SSVC: 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%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
13%
KEV
Not listed

Published

February 19, 2026

Last Modified

June 17, 2026

Advisory Details (4)

Auto-updated Aug 7, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
generic

[Bug] Heap-buffer-overflow (Off-by-one) in xlnt::detail::decode_base64 (base64.cpp:176) · Issue #137 · xlnt-community/xlnt · GitHub

https://github.com/xlnt-community/xlnt/issues/137
github_commit

commit f2d7bf494e5c (xlnt-community/xlnt)

Fix landed in xlnt-community/xlnt commit f2d7bf494e5c — awaiting tagged release

https://github.com/xlnt-community/xlnt/commit/f2d7bf494e5c52706843cf7eb9892821bffb0734
generic

GitHub - xlnt-community/xlnt: :bar_chart: Cross-platform user-friendly xlsx library for C++11+ · GitHub

https://github.com/xlnt-community/xlnt/
generic

0128/xl1/repro at main · oneafter/0128 · GitHub

https://github.com/oneafter/0128/blob/main/xl1/repro

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 30× 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 184 total refreshes for this CVE.

  1. 2026-09-18 20:36 UTCOSV refresh
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 19:27 UTCEPSS rescore
  4. 2026-09-17 19:30 UTCEPSS rescore
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  19. 2026-08-30 23:50 UTCOSV refresh
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  1. 2026-08-24 14:17 UTCEPSS rescore
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  11. 2026-08-14 09:41 UTCEG score recompute
  12. 2026-08-14 09:41 UTCGHSA enrichment
  13. 2026-08-13 22:00 UTCEPSS rescore
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  15. 2026-08-13 03:35 UTCGHSA enrichment
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  17. 2026-08-12 02:22 UTCEG score recompute
  18. 2026-08-12 02:22 UTCGHSA enrichment
  19. 2026-08-11 00:00 UTCEPSS rescore
  20. 2026-08-10 10:27 UTCEG score recompute
  21. 2026-08-10 10:27 UTCGHSA enrichment
  22. 2026-08-09 13:46 UTCEPSS rescore
  23. 2026-08-09 09:14 UTCEG score recompute
  24. 2026-08-09 09:14 UTCGHSA enrichment
  25. 2026-08-08 16:37 UTCEPSS rescore
  26. 2026-08-07 21:32 UTCEG score recompute
  27. 2026-08-07 21:32 UTCGHSA enrichment
  28. 2026-08-06 13:46 UTCEPSS rescore
  29. 2026-08-06 03:30 UTCEG score recompute
  30. 2026-08-06 03:30 UTCGHSA enrichment
  31. 2026-08-05 19:17 UTCEPSS rescore
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  34. 2026-08-02 20:13 UTCEG score recompute▲ 2.20
  35. 2026-08-02 20:13 UTCGHSA enrichment
  36. 2026-08-02 02:26 UTCEPSS rescore
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  46. 2026-07-23 14:18 UTCEPSS rescore
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  48. 2026-07-23 03:07 UTCEG score recompute
  49. 2026-07-22 14:08 UTCEPSS rescore
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  62. 2026-07-16 10:23 UTCOSV refresh
  63. 2026-07-15 16:57 UTCEPSS rescore
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  72. 2026-07-09 19:10 UTCEPSS rescore
  73. 2026-07-08 15:15 UTCEPSS rescore
  74. 2026-07-07 13:46 UTCEPSS rescore
  75. 2026-07-06 16:27 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2026-2703?
CVE-2026-2703 is a medium vulnerability published on February 19, 2026. A weakness has been identified in xlnt-community xlnt up to 1.6.1. Impacted is the function xlnt::detail::decode_base64 of the file source/detail/cryptography/base64.cpp of the component Encrypted XLSX File Parser. Executing a manipulation can lead to off-by-one. The attack requires local access.…
When was CVE-2026-2703 disclosed?
CVE-2026-2703 was first published in the National Vulnerability Database on February 19, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-2703 actively exploited?
CVE-2026-2703 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 87.5% of all scored CVEs.
What is the CVSS score of CVE-2026-2703?
CVE-2026-2703 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-2703?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-2703, 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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