CVE-2026-3849

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory published 2026-03-19. the CNA's CVSS baseline 6.9; sources differ by 2.9.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:wolfssl, ghsa
Trending — 4 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: None knownExposed: 0

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

Stack Buffer Overflow in wc_HpkeLabeledExtract via Oversized ECH Config. A vulnerability existed in wolfSSL 5.8.4 ECH (Encrypted Client Hello) support, where a maliciously crafted ECH config could cause a stack buffer overflow on the client side, leading to potential remote execution and client program crash. This could be exploited by a malicious TLS server supporting ECH. Note that ECH is off by default, and is only enabled with enable-ech.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
59(Track)
EG Risk 59/100SSVC: 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
Severity98% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
36%
KEV
Not listed

Published

March 19, 2026

Last Modified

June 17, 2026

Advisory Details (1)

Auto-updated Jul 27, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr.
github_pr

TLS ECH Testing Improvements

Fix merged in wolfSSL/wolfssl PR #9737 on 2026-03-11 — awaiting tagged release

https://github.com/wolfSSL/wolfssl/pull/9737

Vendor Advisories for CVE-2026-3849(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 7× in last 7d / 7× 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. 2026-08-01 04:16 UTCEPSS rescore
  2. 2026-07-30 16:28 UTCEPSS rescore
  3. 2026-07-30 01:30 UTCEPSS rescore
  4. 2026-07-27 14:13 UTCEPSS rescore
  5. 2026-07-27 12:51 UTCEG score recompute
  6. 2026-07-27 12:51 UTCGHSA enrichment
  7. 2026-07-27 12:50 UTCOSV refresh

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-3849?
CVE-2026-3849 is a critical vulnerability published on March 19, 2026. Stack Buffer Overflow in wc_HpkeLabeledExtract via Oversized ECH Config. A vulnerability existed in wolfSSL 5.8.4 ECH (Encrypted Client Hello) support, where a maliciously crafted ECH config could cause a stack buffer overflow on the client side, leading to potential remote execution and client…
When was CVE-2026-3849 disclosed?
CVE-2026-3849 was first published in the National Vulnerability Database on March 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-2026-3849 actively exploited?
CVE-2026-3849 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 63.5% of all scored CVEs.
What is the CVSS score of CVE-2026-3849?
CVE-2026-3849 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-3849?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-3849, 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-2026-3849

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