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CVE.org (no NVD analysis yet)· CNA apache

CVE-2026-73637: Apache HTTP Server: mod_auth_digest DoS attack

Noroxi assessment

Priority: Monitor (action score 29/100)

  • 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: 0.46% (FIRST EPSS).
  • 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.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Apache Software Foundation Apache HTTP Server 2.4.69; azl3 httpd 2.4.68-1 on Azure Linux 3.0 2.4.69-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Apache Software Foundation Apache HTTP Server 2.4.69; azl3 httpd 2.4.68-1 on Azure Linux 3.0 2.4.69-1 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

Use after free in mod_auth_digest in Apache Software Foundation Apache HTTP Server before 2.4.69 on all platforms allows an unauthenticated remote client to cause authentication state corruption via concurrent Digest authentication requests when AuthDigestNcCheck is enabled or AuthDigestNonceLifetime is set to 0. Users are recommended to upgrade to version 2.4.69, which fixes this issue.

HighCVSS 7.3 · v3.1—No exploit Fix available
Published
Oct 1, 2026
Updated
Oct 5, 2026
EPSS
0.4% · 40th percentile

Report tools

JSON

Action score

29

Monitor

Low priority for now.

CVSS
29 / 40 · 7.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-73637

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?

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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.

VendorProduct
apachehttp server

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When you'll hear from us

  • when a new CVE affecting this product is published
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  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
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Affected versions

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

  • apache http server2.4.0 and later · before 2.4.69

Versions reported by the vendor

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

  • Apache Software Foundation Apache HTTP Server

    • 2.4.0 and later · up to and including 2.4.68affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:10httpdbefore 2.4.63-13.el10_2.82.4.63-13.el10_2.8
AlmaLinux:10httpd-corebefore 2.4.63-13.el10_2.82.4.63-13.el10_2.8
AlmaLinux:10httpd-develbefore 2.4.63-13.el10_2.82.4.63-13.el10_2.8
AlmaLinux:10httpd-filesystembefore 2.4.63-13.el10_2.82.4.63-13.el10_2.8
AlmaLinux:10httpd-manualbefore 2.4.63-13.el10_2.82.4.63-13.el10_2.8
AlmaLinux:10httpd-toolsbefore 2.4.63-13.el10_2.82.4.63-13.el10_2.8
AlmaLinux:10mod_ldapbefore 2.4.63-13.el10_2.82.4.63-13.el10_2.8
AlmaLinux:10mod_luabefore 2.4.63-13.el10_2.82.4.63-13.el10_2.8
AlmaLinux:10mod_proxy_htmlbefore 1:2.4.63-13.el10_2.81:2.4.63-13.el10_2.8
AlmaLinux:10mod_sessionbefore 2.4.63-13.el10_2.82.4.63-13.el10_2.8
AlmaLinux:10mod_sslbefore 1:2.4.63-13.el10_2.81:2.4.63-13.el10_2.8
AlmaLinux:9httpdbefore 2.4.62-13.el9_8.92.4.62-13.el9_8.9
AlmaLinux:9httpd-corebefore 2.4.62-13.el9_8.92.4.62-13.el9_8.9
AlmaLinux:9httpd-develbefore 2.4.62-13.el9_8.92.4.62-13.el9_8.9
AlmaLinux:9httpd-filesystembefore 2.4.62-13.el9_8.92.4.62-13.el9_8.9
AlmaLinux:9httpd-manualbefore 2.4.62-13.el9_8.92.4.62-13.el9_8.9
AlmaLinux:9httpd-toolsbefore 2.4.62-13.el9_8.92.4.62-13.el9_8.9
AlmaLinux:9mod_ldapbefore 2.4.62-13.el9_8.92.4.62-13.el9_8.9
AlmaLinux:9mod_luabefore 2.4.62-13.el9_8.92.4.62-13.el9_8.9
AlmaLinux:9mod_proxy_htmlbefore 1:2.4.62-13.el9_8.91:2.4.62-13.el9_8.9
AlmaLinux:9mod_sessionbefore 2.4.62-13.el9_8.92.4.62-13.el9_8.9
AlmaLinux:9mod_sslbefore 1:2.4.62-13.el9_8.91:2.4.62-13.el9_8.9
Alpine:v3.21apache2before 2.4.69-r02.4.69-r0
Debian:12apache2from 0—

+15

Same product

apache: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-42013Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773)KEV
    99Now
  • CVE-2021-41773Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49KEV
    99Now
  • CVE-2024-38475Apache HTTP Server weakness in mod_rewrite when first segment of substitution matches filesystem path.KEV
    96Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-63718Oct 1, 2026 · Apache HTTP Server: mod_proxy_uwsgi Transfer-Encoding response smuggling
    30Monitor
  • ← EarlierCVE-2026-73636Oct 1, 2026 · Apache HTTP Server: mod_auth_digest one-time-nonce replay attack
    32Monitor
  • Later →CVE-2026-79768Oct 1, 2026 · Apache HTTP Server: mod_userdir information disclosure
    21Monitor

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
Apache Software Foundation Apache HTTP Server2.4.69 · descriptionVendor (CNA)
azl3 httpd 2.4.68-1 on Azure Linux 3.02.4.69-1 · Release NotesMicrosoft (MSRC)
almalinux:httpd2.4.62-13.el9_8.9 · AlmaLinux:9Package registry (OSV)
almalinux:httpd-core2.4.62-13.el9_8.9 · AlmaLinux:9Package registry (OSV)
almalinux:httpd-devel2.4.62-13.el9_8.9 · AlmaLinux:9Package registry (OSV)
almalinux:httpd-filesystem2.4.62-13.el9_8.9 · AlmaLinux:9Package registry (OSV)
almalinux:httpd-manual2.4.62-13.el9_8.9 · AlmaLinux:9Package registry (OSV)
almalinux:httpd-tools2.4.62-13.el9_8.9 · AlmaLinux:9Package registry (OSV)
almalinux:mod_ldap2.4.62-13.el9_8.9 · AlmaLinux:9Package registry (OSV)
almalinux:mod_lua2.4.62-13.el9_8.9 · AlmaLinux:9Package registry (OSV)
almalinux:mod_proxy_html1:2.4.62-13.el9_8.9 · AlmaLinux:9Package registry (OSV)
almalinux:mod_session2.4.62-13.el9_8.9 · AlmaLinux:9Package registry (OSV)
almalinux:mod_ssl1:2.4.62-13.el9_8.9 · AlmaLinux:9Package registry (OSV)
alpine:apache22.4.69-r0 · Alpine:v3.21Package registry (OSV)
debian:apache22.4.69-1 · Debian:14Package registry (OSV)
debian:apache22.4.69-1~deb13u1 · Debian:13Package registry (OSV)
red hat:httpd0:2.4.69-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:httpd-core0:2.4.69-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:httpd-devel0:2.4.69-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:httpd-filesystem0:2.4.69-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:httpd-manual0:2.4.69-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:httpd-tools0:2.4.69-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:mod_ldap0:2.4.69-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:mod_lua0:2.4.69-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:mod_proxy_html0:2.4.69-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:mod_session0:2.4.69-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:mod_ssl0:2.4.69-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
rocky linux:httpd0:2.4.62-13.el9_8.9 · Rocky Linux:9Package 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.

  1. Published
  2. Fix recordedsame day
  3. TodayOct 29, 2026+27 d
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.

  • CVE-2026-561540 days apartApache HTTP Server: mod_rewrite use-after-free via %{LA-U:HTTP:...}
    39Monitor
  • CVE-2026-579410 days apartApache HTTP Server: mod_http2 use-after-free / wild write via shared session->bbtmp re-entrancy
    39Monitor
  • CVE-2026-29167115 days apartApache HTTP Server: mod_ldap per-dir use-after-free
    39Monitor
  • CVE-2026-48913115 days apartApache HTTP Server: mod_http2 memory corruption when file handles exhausted
    29Monitor

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

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

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&dev->lock);

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. CVSS— → 7.3
  2. Severity— → high
  3. SSVC exploitation— → none
  4. Exploit maturity— → none
  5. 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