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NVD / CVE Program· CNA apache

CVE-2026-23918: Apache HTTP Server: http2: double free and possible RCE on early reset

HighCVSS 8.8 · v3.1—Proof of concept Fix available

Noroxi assessment

Priority: Plan (action score 50/100)

  • Public proof-of-concept code exists (Exploit-DB, GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 49.7% (FIRST EPSS); higher than 98.9% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Apache Software Foundation Apache HTTP Server 2.4.67; azl3 httpd 2.4.66-1 on Azure Linux 3.0 2.4.67-1.

Add it to your regular patch cycle. Upgrade to Apache Software Foundation Apache HTTP Server 2.4.67; azl3 httpd 2.4.66-1 on Azure Linux 3.0 2.4.67-1 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

Double Free and possible RCE vulnerability in Apache HTTP Server with the HTTP/2 protocol. This issue affects Apache HTTP Server: 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the issue.

Published
May 4, 2026
Updated
Oct 26, 2026
EPSS
49.7% · 98th percentile

Report tools

JSON

Action score

50

Plan

Add it to your regular patch cycle.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
15 / 30 · 49.7%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

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

Follow CVE-2026-23918

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

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

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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

Using http server? Add it to your stack and be the first to know about CVEs like this one. (Apache HTTP)

Watch new CVEs for http server

When you'll hear from us

  • when a new CVE affecting this product is published
  • when a record in your stack enters KEV or is weaponized

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Is Apache HTTP Server on your server exposed to the internet?Run a port scan

Your free account also gets you

  • CVE alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every Monday

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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

    • 2.4.66affected

Affected versions

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

  • apache http server2.4.66

Package-level exposure

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

EcosystemPackageAffected rangeFix
Alpine:v3.20apache2before 2.4.67-r02.4.67-r0
Debian:12apache2before 2.4.67-1~deb12u22.4.67-1~deb12u2
Debian:13apache2before 2.4.66-1~deb13u22.4.66-1~deb13u2
Debian:14apache2before 2.4.66-52.4.66-5
openSUSE:Leap 16.0apache2before 2.4.66-160000.2.12.4.66-160000.2.1
openSUSE:Leap 16.0apache2-develbefore 2.4.66-160000.2.12.4.66-160000.2.1
openSUSE:Leap 16.0apache2-eventbefore 2.4.66-160000.2.12.4.66-160000.2.1
openSUSE:Leap 16.0apache2-manualbefore 2.4.66-160000.2.12.4.66-160000.2.1
openSUSE:Leap 16.0apache2-preforkbefore 2.4.66-160000.2.12.4.66-160000.2.1
openSUSE:Leap 16.0apache2-utilsbefore 2.4.66-160000.2.12.4.66-160000.2.1
openSUSE:Leap 16.0apache2-workerbefore 2.4.66-160000.2.12.4.66-160000.2.1
openSUSE:Tumbleweedapache2before 2.4.67-1.12.4.67-1.1
Red Hat:hummingbird:1httpdbefore 0:2.4.67-0.1.hum10:2.4.67-0.1.hum1
Red Hat:hummingbird:1httpd-corebefore 0:2.4.67-0.1.hum10:2.4.67-0.1.hum1
Red Hat:hummingbird:1httpd-develbefore 0:2.4.67-0.1.hum10:2.4.67-0.1.hum1
Red Hat:hummingbird:1httpd-filesystembefore 0:2.4.67-0.1.hum10:2.4.67-0.1.hum1
Red Hat:hummingbird:1httpd-manualbefore 0:2.4.67-0.1.hum10:2.4.67-0.1.hum1
Red Hat:hummingbird:1httpd-toolsbefore 0:2.4.67-0.1.hum10:2.4.67-0.1.hum1
SUSE:Linux Enterprise Server 12 SP5-LTSSapache2before 2.4.66-35.78.12.4.66-35.78.1
SUSE:Linux Enterprise Server 12 SP5-LTSSapache2-tls13before 2.4.66-35.78.12.4.66-35.78.1
SUSE:Linux Enterprise Server 16.0apache2before 2.4.66-160000.2.12.4.66-160000.2.1
SUSE:Linux Enterprise Server 16.0apache2-develbefore 2.4.66-160000.2.12.4.66-160000.2.1
SUSE:Linux Enterprise Server 16.0apache2-eventbefore 2.4.66-160000.2.12.4.66-160000.2.1
SUSE:Linux Enterprise Server 16.0apache2-manualbefore 2.4.66-160000.2.12.4.66-160000.2.1

+3

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-2026-33857May 4, 2026 · Apache HTTP Server: Off-by-one OOB reads in AJP getter functions
    21Monitor
  • ← EarlierCVE-2026-34032May 4, 2026 · Apache HTTP Server: mod_proxy_ajp: Heap Buffer Over-Read Due to Missing Null-Termination Check (ajp_msg_get_string)
    21Monitor
  • Later →CVE-2026-29169May 4, 2026 · Apache HTTP Server: mod_dav_lock indirect lock crash
    30Monitor

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 Server2.4.67 · descriptionVendor (CNA)
azl3 httpd 2.4.66-1 on Azure Linux 3.02.4.67-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
alpine:apache22.4.67-r0 · Alpine:v3.20Package registry (OSV)
debian:apache22.4.67-1~deb12u2 · Debian:12Package registry (OSV)
opensuse:apache22.4.67-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:apache2-devel2.4.66-160000.2.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:apache2-event2.4.66-160000.2.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:apache2-manual2.4.66-160000.2.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:apache2-prefork2.4.66-160000.2.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:apache2-utils2.4.66-160000.2.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:apache2-worker2.4.66-160000.2.1 · openSUSE:Leap 16.0Package registry (OSV)
red hat:httpd0:2.4.67-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:httpd-core0:2.4.67-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:httpd-devel0:2.4.67-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:httpd-filesystem0:2.4.67-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:httpd-manual0:2.4.67-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:httpd-tools0:2.4.67-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
suse:apache22.4.66-160000.2.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:apache2-devel2.4.66-160000.2.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:apache2-event2.4.66-160000.2.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:apache2-manual2.4.66-160000.2.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:apache2-prefork2.4.66-160000.2.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:apache2-tls132.4.66-35.78.1 · SUSE:Linux Enterprise Server 12 SP5-LTSSPackage registry (OSV)
suse:apache2-utils2.4.66-160000.2.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:apache2-worker2.4.66-160000.2.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Exploit-DB entry ×1
  • Proof-of-concept repository on GitHub ×15

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHub15 repositories2026-05-05 → 2026-06-28
Exploit-DB entrywebapps2026-05-26

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. First PoCsame day
  3. TodayNov 14, 2026+193 d
EPSS, last 120 days

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

Credits

All researchers

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

Chain candidates

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

  • CVE-2026-73636150 days apartApache HTTP Server: mod_auth_digest one-time-nonce replay attack
    32Monitor
  • CVE-2026-48005150 days apartApache HTTP Server: mod_auth_digest reauthentication attack
    30Monitor
  • CVE-2025-66200150 days apartApache HTTP Server: mod_userdir+suexec bypass via AllowOverride FileInfo
    21Monitor

Not on record for this CVE: patch commit or PR link · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-415 · Double Free

CVSS vector

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

References

Show all references (5 more)

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

All records