CVE-2026-102559

HIGHPre-NVD 8.68.6—
EchelonGraph scoreHIGH confidence

Score 8.6 from GitHub Security Advisory (severity: HIGH) published 2026-09-29. A secondary CVSS source baseline 8.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
8.6EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 8.6Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

A flaw was found in libsoup. When constructing a masked WebSocket client frame for a very large outgoing payload, size values passed to GByteArray allocation APIs could be truncated while the masking routine still used the full length, causing a heap buffer overflow.

CVSS v3
8.6
EG Score
8.6HIGHhigh confidence
EG Risk
54
EG Risk 54/100CISA SSVC

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
Severity86% × 45%
Exploitation0% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.3%
EPSS %ILE
20th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 29, 2026

Last Modified

September 30, 2026

Advisory Details (2)

Auto-updated Sep 29, 2026
Patch available. Sources: redhat.
redhat

2543285 – (CVE-2026-102559) CVE-2026-102559 libsoup: libsoup: Heap buffer overflow during WebSocket client-frame masking

https://bugzilla.redhat.com/show_bug.cgi?id=2543285
redhat Patch Available

CVE-2026-102559 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-102559

Vendor Advisories for CVE-2026-102559(2)

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 24× in last 7d / 24× 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.

  1. 2026-10-04 04:16 UTCVendor advisory
  2. 2026-10-04 04:16 UTCGHSA enrichment
  3. 2026-10-03 15:13 UTCEG score recompute
  4. 2026-10-03 15:13 UTCVendor advisory
  5. 2026-10-03 15:13 UTCGHSA enrichment
  6. 2026-10-03 14:25 UTCEPSS rescore
  7. 2026-10-03 02:11 UTCEG score recompute
  8. 2026-10-03 02:11 UTCGHSA enrichment
  9. 2026-10-02 13:08 UTCGHSA enrichment
  10. 2026-10-02 00:01 UTCEG score recompute
  11. 2026-10-02 00:01 UTCGHSA enrichment
  12. 2026-10-01 19:49 UTCEPSS rescore
  13. 2026-10-01 10:34 UTCGHSA enrichment
  14. 2026-09-30 21:29 UTCEG score recompute
  15. 2026-09-30 21:29 UTCGHSA enrichment
  16. 2026-09-30 20:27 UTCEG score recompute
  17. 2026-09-30 20:27 UTCGHSA enrichment
  18. 2026-09-30 15:02 UTCEPSS rescore
  19. 2026-09-30 10:51 UTCGHSA enrichment
  20. 2026-09-29 21:47 UTCEG score recompute
  21. 2026-09-29 21:46 UTCGHSA enrichment
  22. 2026-09-29 18:31 UTCEG score recompute
  23. 2026-09-29 17:30 UTCEG score recompute
  24. 2026-09-29 17:28 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-102559?
CVE-2026-102559 is a high vulnerability published on September 29, 2026. A flaw was found in libsoup. When constructing a masked WebSocket client frame for a very large outgoing payload, size values passed to GByteArray allocation APIs could be truncated while the masking routine still used the full length, causing a heap buffer overflow.
When was CVE-2026-102559 disclosed?
CVE-2026-102559 was first published on September 29, 2026, with the most recent update on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-102559 actively exploited?
CVE-2026-102559 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (20th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-102559?
CVE-2026-102559 has a CVSS base score of 8.6 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-102559?
A fix for CVE-2026-102559 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-102559 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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