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NVD / CVE Program· CNA glibc

CVE-2026-8674: Assertion failure in the DNS stub resolver with a long search domain

Noroxi assessment

Priority: Monitor (action score 21/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.31% (FIRST EPSS).
  • Someone on the same network segment can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: azl3 glibc 2.38-21 on Azure Linux 3.0 Release Notes.

Low priority for now. Upgrade to azl3 glibc 2.38-21 on Azure Linux 3.0 Release Notes or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Initializing the DNS stub resolver from an /etc/resolv.conf file, or a LOCALDOMAIN environment variable, whose search list contains a domain of roughly 200 characters or more in the GNU C Library version 2.26 to 2.44 results in an assertion failure which aborts the process. The resolver truncates the search list when copying it into the fixed-size _res.defdname buffer, then asserts that the copy is consistent with the full configuration. The consistency check compared against the wrong size and did not handle a first entry that does not fit, so a correctly truncated list failed the assertion. Any process that resolves names through the library is affected, including long-running processes that reload /etc/resolv.conf on the next query after it changes. Search domains are commonly written to /etc/resolv.conf from data received over DHCP or from a VPN server, so an attacker on the local network may be able to trigger this without privileges on the target system, subject to validation by the network configuration software.

MediumCVSS 5.3 · v3.1—No exploit Fix available
Published
Sep 17, 2026
Updated
Sep 18, 2026
EPSS
0.3% · 24th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · glibc
5.3
NVD has not scored this yet; the score shown is the CNA’s.

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

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

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

  • The GNU C Library glibc

    • 2.26 and later · up to and including 2.44affected

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:10glibcbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-all-langpacksbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-benchtestsbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-commonbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-develbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-docbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-gconv-extrabefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-aabefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-afbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-agrbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-akbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-ambefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-anbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-anpbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-arbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-asbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-astbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-aycbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-azbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-bebefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-bembefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-berbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-bgbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1
AlmaLinux:10glibc-langpack-bhbbefore 2.39-145.el10_2.alma.12.39-145.el10_2.alma.1

+96

Same product

the gnu c library: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-19499Buffer overflow in strfmon and strfmon_l right-justification padding
    30Monitor
  • CVE-2026-6791Potential stack-based buffer clash during tilde expansion in wordexp
    26Monitor
  • CVE-2026-86805AT_SECURE programs may load attacker-controlled code via $ORIGIN
    25Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-77117Sep 15, 2026 · SHIFT_JISX0213 decoding may hang on crafted input
    23Monitor
  • ← EarlierCVE-2026-80489Sep 15, 2026 · EUC_JISX0213 decoding may hang on crafted input
    23Monitor
  • Later →CVE-2026-95818Sep 22, 2026 · AT_SECURE program buffer overflow via $ORIGIN processing
    14Monitor

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
azl3 glibc 2.38-21 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
almalinux:glibc2.39-145.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-all-langpacks2.39-145.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-benchtests2.39-145.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-common2.39-145.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-devel2.39-145.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-doc2.39-145.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-gconv-extra2.39-145.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-langpack-aa2.39-145.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-langpack-af2.39-145.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-langpack-agr2.39-145.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-langpack-ak2.39-145.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-langpack-am2.39-145.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
debian:glibc2.43-6 · Debian:14Package registry (OSV)
opensuse:glibc2.40-160000.7.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:glibc2.44-3.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:glibc-cross-aarch64-src2.40-160000.7.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:glibc-cross-ppc64le-src2.40-160000.7.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:glibc-cross-riscv64-src2.40-160000.7.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:glibc-cross-s390x-src2.40-160000.7.1 · openSUSE:Leap 16.0Package registry (OSV)
red hat:compat-libpthread-nonshared0:2.43-8.6.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc0:2.43-8.6.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-all-langpacks0:2.43-8.6.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-benchtests0:2.43-8.6.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-common0:2.43-8.6.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-devel0:2.43-8.6.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-doc0:2.43-8.6.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-gconv-extra0:2.43-8.6.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-langpack-aa0:2.43-8.6.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-langpack-af0:2.43-8.6.hum1 · Red Hat:hummingbird:1Package registry (OSV)

+4

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

  • Someone on the same network segment can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

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

Weakness class (CWE)

CWE-617 · Reachable Assertion

CVSS vector

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

nvd-secondary

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.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (4 more)

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

All records