CVE-2026-3849 json
Buffer Overflow in HPKE via Oversized ECH Config
published 2026-03-19 7 mo ago modified 2026-07-25 3 mo ago also EUVD-2026-13231 , GHSA-267h-vrw9-53p3 , JLSEC-2026-711
- cvss
- 9.8
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 40%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- julia wolfSSL_jll 5.9.2+0
- wolfssl wolfssl 5.9.0
- wolfssl Alpine 3.23 5.9.1-r0
- wolfssl Alpine 3.24 5.9.0-r0
alpine advisories ALPINE-CVE-2026-3849
Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0
- github.com/wolfSSL/wolfssl#9737 pull request
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 7 mo ago
Exploit prediction
0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/V:D/RE:M/U:Amber |
| CNA | 4.0 | 6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:D/RE:M/U:Amber |
| NVD | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| OSV | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| julia | wolfSSL_jll | >=5.7.2+0, <5.9.2+0 |
5.9.2+0 |
Affected products
- wolfSSL Inc. wolfSSL
Classification
- Weakness
-
- CWE-787 Out-of-bounds Write
References
-
github.com
/wolfSSL/wolfssl/pull/9737
issue-tracking, patch, web
-
github.com
/advisories/GHSA-267h-vrw9-53p3
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-3849
web
Sources
- CVE List CVE-2026-3849
- NVD CVE-2026-3849
- OSV JLSEC-2026-711
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.