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CVE-2026-42002· NVD / CVE Program· CNA OX

Concurrency and locking defects in GSS-TSIG

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
May 21, 2026
Updated
Jul 23, 2026
EPSS
0.6% · 46th percentile
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Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.6%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.5
CNA · OX
5.9
1.6 point gap

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
powerdnsauthoritative

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • powerdns authoritative4.7.0 and later · before 4.9.15
  • powerdns authoritative5.0.0 and later · before 5.0.5

Versions reported by the vendor

Affected version ranges reported by the assigning authority (OX). Independent of NVD's CPE analysis and usually ahead of it.

  • PowerDNS Authoritative

    • 4.9.0 and later · before 4.9.15affected · semver
    • 5.0.0 and later · before 5.0.5affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12pdnsall versions—
Debian:13pdnsbefore 4.9.15-0+deb13u14.9.15-0+deb13u1
Debian:14pdnsbefore 5.0.5-15.0.5-1

Same product

powerdns: all records

Other highest-scoring records for the same primary product.

  • CVE-2015-1868The label decompression functionality in PowerDNS Recursor 3.5.x, 3.6.x before 3.6.3, and 3.7.x before 3.7.2 and Authoritative (Auth) Server
    56Plan
  • CVE-2016-5427PowerDNS (aka pdns) Authoritative Server before 3.4.10 does not properly handle a .
    49Plan
  • CVE-2020-24698An issue was discovered in PowerDNS Authoritative through 4.3.0 when --enable-experimental-gss-tsig is used.
    40Plan
  • CVE-2015-5311PowerDNS (aka pdns) Authoritative Server 3.4.4 before 3.4.7 allows remote attackers to cause a denial of service (assertion failure and serv
    40Plan
  • CVE-2026-33608Incomplete domain name sanitization during
    39Monitor
  • CVE-2016-5426PowerDNS (aka pdns) Authoritative Server before 3.4.10 allows remote attackers to cause a denial of service (backend CPU consumption) via a
    39Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
PowerDNS Authoritative4.9.15Vendor (CNA)
PowerDNS Authoritative5.0.5Vendor (CNA)
debian:pdns4.9.15-0+deb13u1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-364 · Signal Handler Race Condition

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

  1. Fix✗ → ✓

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References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records