October 13, 2026

CVE Watchtower

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CVE-2026-28387NVD

Vulnerability Summary

Issue summary: An uncommon configuration of clients performing DANE TLSA-based
server authentication, when paired with uncommon server DANE TLSA records, may
result in a use-after-free and/or double-free on the client side.

Impact summary: A use after free can have a range of potential consequences
such as the corruption of valid data, crashes or execution of arbitrary code.

However, the issue only affects clients that make use of TLSA records with both
the PKIX-TA(0/PKIX-EE(1) certificate usages and the DANE-TA(2) certificate
usage.

By far the most common deployment of DANE is in SMTP MTAs for which RFC7672
recommends that clients treat as 'unusable' any TLSA records that have the PKIX
certificate usages. These SMTP (or other similar) clients are not vulnerable
to this issue. Conversely, any clients that support only the PKIX usages, and
ignore the DANE-TA(2) usage are also not vulnerable.

The client would also need to be communicating with a server that publishes a
TLSA RRset with both types of TLSA records.

No FIPS modules are affected by this issue, the problem code is outside the
FIPS module boundary.
Severity Level
HIGH(8.1)
Published Date
Apr 7, 2026
Last Modified
Jul 24, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
0.67%Probability
Root Weakness (CWE)
CWE-416: Unknown/Unlisted Weakness ↗
Refer to the official MITRE database for detailed architectural specifications regarding this weakness.
CVSS v3.1 Base Metrics — Score 8.1 (HIGH)
Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

Affected & Patched Versions

Affected Versions
  • Openssl Openssl >= 1.1.1 and < 1.1.1zg
  • Openssl Openssl >= 3.0.0 and < 3.0.20
  • Openssl Openssl >= 3.3.0 and < 3.3.7
  • Openssl Openssl >= 3.4.0 and < 3.4.5
  • Openssl Openssl >= 3.5.0 and < 3.5.6
  • Openssl Openssl >= 3.6.0 and < 3.6.2
Patched Versions
  • Openssl Openssl 1.1.1zg
  • Openssl Openssl 3.0.20
  • Openssl Openssl 3.3.7
  • Openssl Openssl 3.4.5
  • Openssl Openssl 3.5.6
  • Openssl Openssl 3.6.2
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🎁7-Day Free Trial — Try Pro or Team, no card required.
📧Email Delivery — Threat intel straight to your inbox.
♾️Unlimited Vendors — Track your entire stack.
🚨All New CVEs — Be the first to know.
📈EPSS Spike Alerts — Catch rising risk before it peaks.
🎯Custom EPSS/CVSS — Filter noise, focus on risk.
🛡️Exploit Intel — A 2nd confirmed-exploit signal beyond KEV.
🐙GitHub Issues — Auto-tracked, no duplicates.
📬Weekly Digest — One clean summary, not inbox spam.
🏷️Watchlist Groups — Tag alerts by team (Infra/AppSec/SOC).
💬Webhooks — Slack & Teams integration.
🔀Smart Routing — Critical alerts to one channel, rest to another.
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External References