BusyBox TLS get_client_hello() reads past the end of the input buffer when parsing a truncated ClientHello message.
CVE-2026-88840
MEDIUMPre-NVD 5.35.3—Trending — 3 sources updated this week
EchelonGraph scoreHIGH confidence
Score 5.3 from GitHub Security Advisory published 2026-09-23. a secondary CVSS source baseline 5.3; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: ghsa, secondary
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 5.3Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.3
- EG Score
- 5.3(high)
- EG Risk
- 28(Track)EG Risk 28/100SSVC: 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 computedSeverity53% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
Published
September 23, 2026
Last Modified
September 23, 2026
Advisory Details (2)
Auto-updated Sep 23, 2026Patch available. Sources: redhat.
redhat
2531354 – (CVE-2026-88840) CVE-2026-88840 busybox: busybox: TLS ssl_server reads one byte out of bounds when parsing truncated ClientHello
https://bugzilla.redhat.com/show_bug.cgi?id=2531354redhat Patch Available
CVE-2026-88840 - 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-2026-88840Vendor Advisories for CVE-2026-88840(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 5× in last 7d / 5× 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.
- 2026-09-23 19:47 UTCEG score recompute
- 2026-09-23 19:47 UTCGHSA enrichment
- 2026-09-23 18:17 UTCEG score recompute
- 2026-09-23 17:49 UTCEG score recompute
- 2026-09-23 17:49 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(4)
What is CVE-2026-88840?
CVE-2026-88840 is a medium vulnerability published on September 23, 2026. BusyBox TLS getclienthello() reads past the end of the input buffer when parsing a truncated ClientHello message.
When was CVE-2026-88840 disclosed?
CVE-2026-88840 was first published in the National Vulnerability Database on September 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-88840?
CVE-2026-88840 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-88840?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-88840, 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
Explore the affected products and dependency analysis for CVE-2026-88840
Is Your Infrastructure Affected by CVE-2026-88840?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.