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NVD / CVE Program· CNA glibc

CVE-2026-19499: Buffer overflow in strfmon and strfmon_l right-justification padding

Noroxi assessment

Priority: Monitor (action score 30/100)

  • 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: 0.29% (FIRST EPSS).
  • Anyone who can reach it over the internet 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

Calling strfmon and strfmon_l in the GNU C Library version 2.38 to 2.44 can write past the end of the caller-supplied output buffer when a conversion uses right-justified width padding. Exploitation requires an application code path that calls strfmon or strfmon_l with right-justified width padding into a destination buffer that is large enough for the padding to succeed but too small for the internal memmove call. The field width or format may be attacker-influenced or a fixed susceptible pattern in the caller. At the time of publication, no network-facing application impact is known.

HighCVSS 7.7 · v3.1—No exploit Fix available
Published
Sep 14, 2026
Updated
Sep 18, 2026
EPSS
0.2% · 22th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · glibc
7.7
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 you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • 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

    • 2.38 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 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-all-langpacksbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-benchtestsbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-commonbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-develbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-docbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-gconv-extrabefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-aabefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-afbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-agrbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-akbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-ambefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-anbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-anpbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-arbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-asbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-astbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-aycbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-azbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-bebefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-bembefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-berbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-bgbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1
AlmaLinux:10glibc-langpack-bhbbefore 2.39-142.el10_2.alma.12.39-142.el10_2.alma.1

+96

Same product

the gnu c library: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-84243gettext: Directory traversal via the LANGUAGE environment variable
    28Monitor
  • 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-2026-18374Aug 27, 2026 · Passing an effectively empty string to the `,ccs=` syntax extension of the mode argument in the `fopen` function in the GNU C Library versio
    19Monitor
  • ← EarlierCVE-2026-89092Sep 11, 2026 · Stack overflow in nscd due to unbounded alloca use
    16Monitor
  • Later →CVE-2026-19542Sep 14, 2026 · Stack-based out-of-bounds write in tdelete during tree rebalancing
    22Monitor

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:glibc2.39-142.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-all-langpacks2.39-142.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-benchtests2.39-142.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-common2.39-142.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-devel2.39-142.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-doc2.39-142.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-gconv-extra2.39-142.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-langpack-aa2.39-142.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-langpack-af2.39-142.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-langpack-agr2.39-142.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-langpack-ak2.39-142.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:glibc-langpack-am2.39-142.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
debian:glibc2.43-5 · Debian:14Package registry (OSV)
opensuse:glibc2.44-2.1 · 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-nonshared0:2.43-8.3.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc0:2.43-8.3.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-all-langpacks0:2.43-8.3.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-benchtests0:2.43-8.3.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-common0:2.43-8.3.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-devel0:2.43-8.3.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-doc0:2.43-8.3.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-gconv-extra0:2.43-8.3.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-langpack-aa0:2.43-8.3.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-langpack-af0:2.43-8.3.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:glibc-langpack-agr0:2.43-8.3.hum1 · Red Hat:hummingbird:1Package registry (OSV)

+3

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.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
low · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
Low
Availability impact
High

Weakness class (CWE)

CWE-122 · Heap-based Buffer Overflow

CVSS vector

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (1 more)

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

All records