CVE-2026-70368

Stunnel: stack-based out-of-bounds read/write in stunnel s_vlog via oversized log message

MEDIUM
6.5
CVSS Score
Published: August 4, 2026 at 01:52 PM UTC
Updated: August 6, 2026 at 03:53 PM UTC
2 products affected across 2 vendorsEnterprise LinuxStunnel

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

A stack-based out-of-bounds read vulnerability exists in the "s_vlog" function of stunnel, when handling oversized log messages via "vsnprintf". A remote attacker with network access to a stunnel service can send protocol inputs that trigger a log message longer than 1024 bytes, leading to an out-of-bounds stack read and a potential crash. In certain corner cases, the same vulnerability could be used to replace a series of trailing "\n" characters with "\0".

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.68 ≤ v < 5.805.68
Affected range stops below 5.80, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 6 (unaffected)
Vendor states this is fixed in 7 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (2)

VDB Entryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/security/cve/CVE-2026-70368
Issue Trackingx_refsource_REDHAT
Source: cverecord
https://bugzilla.redhat.com/show_bug.cgi?id=2462029

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMredhat
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
LOW
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-125

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