CVE-2026-49975: Apache HTTP Server: mod_http2 denial of service
Noroxi assessment
Priority: Plan (action score 40/100)
- Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
- Probability of exploitation in the next 30 days: 32.9% (FIRST EPSS); higher than 98.3% of all records.
- 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: azl3 httpd 2.4.67-1 on Azure Linux 3.0 2.4.68-1; azl3 nginx 1.28.3-4 on Azure Linux 3.0 1.28.3-5.
Add it to your regular patch cycle. Upgrade to azl3 httpd 2.4.67-1 on Azure Linux 3.0 2.4.68-1; azl3 nginx 1.28.3-4 on Azure Linux 3.0 1.28.3-5 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
Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http leads to denial of service via malicious HTTP requests. This issue affects Apache HTTP Server: from 2.4.17 through 2.4.67.
- BDU:2026-07789
- ALSA-2026:25057
- ALSA-2026:25090
- ALSA-2026:25225
- openSUSE-SU-2026:21235-1
- RHSA-2026:25042
- RHSA-2026:25057
- RHSA-2026:25090
- RHSA-2026:25225
- RHSA-2026:27200
- RHSA-2026:36373
- RHSA-2026:36831
- RHSA-2026:36846
- RHSA-2026:50538
- RHSA-2026:50572
- RHSA-2026:55930
- RHSA-2026:55992
- RLSA-2026:25057
- RLSA-2026:25090
- RLSA-2026:25225
- Published
- Jun 8, 2026
- Updated
- Aug 19, 2026
- EPSS
- 32.9% · 98th percentile
- CWE
- CWE-789
Report tools
Action score
40
Plan
Add it to your regular patch cycle.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 10 / 30 · 32.9%
CISA SSVC decision
- Exploitation
- proof of concept
- 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
- 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.
Running WordPress? Scan your site free with WP Lens
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.
We use this product, ask for helpAffected 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.
| Vendor | Product | CPE |
|---|---|---|
| apache | http server | cpe:2.3:a:apache:http_server |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
Using http server? Add it to your stack and be the first to know about CVEs like this one. (Apache HTTP)
Is Apache HTTP Server on your server exposed to the internet?
The free port scanner finds the open ports on your server and matches the service versions it can read against known vulnerabilities. No account needed.
Run a port scanAffected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- apache http server2.4.17 and later · before 2.4.68
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
- 2.4.17 and later · up to and including 2.4.67affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:10 | mod_http2 | before 2.0.29-4.el10_2.1 | 2.0.29-4.el10_2.1 |
| AlmaLinux:8 | httpd | before 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
| AlmaLinux:8 | httpd | before 2.4.37-65.module_el8.10.0+4190+704ad79b.8 | 2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
| AlmaLinux:8 | httpd-devel | before 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
| AlmaLinux:8 | httpd-devel | before 2.4.37-65.module_el8.10.0+4190+704ad79b.8 | 2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
| AlmaLinux:8 | httpd-filesystem | before 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
| AlmaLinux:8 | httpd-manual | before 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
| AlmaLinux:8 | httpd-tools | before 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
| AlmaLinux:8 | httpd-tools | before 2.4.37-65.module_el8.10.0+4190+704ad79b.8 | 2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
| AlmaLinux:8 | mod_http2 | before 1.15.7-10.module_el8.10.0+4190+704ad79b.6 | 1.15.7-10.module_el8.10.0+4190+704ad79b.6 |
| AlmaLinux:8 | mod_ldap | before 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
| AlmaLinux:8 | mod_ldap | before 2.4.37-65.module_el8.10.0+4190+704ad79b.8 | 2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
| AlmaLinux:8 | mod_md | before 1:2.0.8-8.module_el8.10.0+4088+57f011c1.2 | 1:2.0.8-8.module_el8.10.0+4088+57f011c1.2 |
| AlmaLinux:8 | mod_proxy_html | before 1:2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | 1:2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
| AlmaLinux:8 | mod_proxy_html | before 1:2.4.37-65.module_el8.10.0+4190+704ad79b.8 | 1:2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
| AlmaLinux:8 | mod_session | before 2.4.37-65.module_el8.10.0+4190+704ad79b.8 | 2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
| AlmaLinux:8 | mod_session | before 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
| AlmaLinux:8 | mod_ssl | before 1:2.4.37-65.module_el8.10.0+4190+704ad79b.8 | 1:2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
| AlmaLinux:8 | mod_ssl | before 1:2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | 1:2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
| AlmaLinux:9 | mod_http2 | before 2.0.26-6.el9_8.1 | 2.0.26-6.el9_8.1 |
| Alpine:v3.21 | apache2 | before 2.4.68-r0 | 2.4.68-r0 |
| Alpine:v3.21 | nginx | before 1.26.3-r1 | 1.26.3-r1 |
| Alpine:v3.22 | nginx | before 1.28.3-r3 | 1.28.3-r3 |
| Alpine:v3.24 | nginx | before 1.30.1-r0 | 1.30.1-r0 |
+96
Same product
apache: all recordsOther 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)KEV99Now
- CVE-2021-41773Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49KEV99Now
- CVE-2024-38475Apache HTTP Server weakness in mod_rewrite when first segment of substitution matches filesystem path.KEV96Now
Published before and after this one in the same product
- ← EarlierCVE-2026-44631Jun 8, 2026 · Apache HTTP Server: Heap Underflow in `ap_regname` via Signed Char Overflow39Monitor
- ← EarlierCVE-2026-48913Jun 8, 2026 · Apache HTTP Server: mod_http2 memory corruption when file handles exhausted29Monitor
- Later →CVE-2026-42356Oct 1, 2026 · Apache HTTP Server: limited RCE for some internal redirects to non-CGI files in CGI directories14Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| azl3 httpd 2.4.67-1 on Azure Linux 3.0 | 2.4.68-1 · CBL-Mariner Releases | Microsoft (MSRC) |
| azl3 nginx 1.28.3-4 on Azure Linux 3.0 | 1.28.3-5 · CBL-Mariner Releases | Microsoft (MSRC) |
| almalinux:httpd | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:httpd-devel | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:httpd-filesystem | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:httpd-manual | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:httpd-tools | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mod_http2 | 2.0.26-6.el9_8.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:mod_ldap | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mod_md | 1:2.0.8-8.module_el8.10.0+4088+57f011c1.2 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mod_proxy_html | 1:2.4.37-65.module_el8.10.0+4185+0955a0d7.8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mod_session | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mod_ssl | 1:2.4.37-65.module_el8.10.0+4185+0955a0d7.8 · AlmaLinux:8 | Package registry (OSV) |
| alpine:apache2 | 2.4.68-r0 · Alpine:v3.21 | Package registry (OSV) |
| alpine:nginx | 1.26.3-r1 · Alpine:v3.21 | Package registry (OSV) |
| debian:apache2 | 2.4.67-1~deb12u3 · Debian:12 | Package registry (OSV) |
| opensuse:apache2 | 2.4.66-160000.3.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:apache2-devel | 2.4.66-160000.3.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:apache2-event | 2.4.66-160000.3.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:apache2-manual | 2.4.66-160000.3.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:apache2-prefork | 2.4.66-160000.3.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:apache2-utils | 2.4.66-160000.3.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:apache2-worker | 2.4.66-160000.3.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| red hat:httpd | 0:2.4.68-1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:httpd-core | 0:2.4.68-1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:httpd-debuginfo | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:httpd-debugsource | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:httpd-devel | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:httpd-devel | 0:2.4.68-1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:httpd-filesystem | 0:2.4.68-1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
+20
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
- Proof-of-concept repository on GitHub ×13
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.
| Source | Kind | Date |
|---|---|---|
| Proof-of-concept repository on GitHub | stars:6 | 2026-06-03 |
| Proof-of-concept repository on GitHub | stars:29 | 2026-06-04 |
| Proof-of-concept repository on GitHub | stars:2 | 2026-06-08 |
| Proof-of-concept repository on GitHub | stars:14 | 2026-06-10 |
| Proof-of-concept repository on GitHub | stars:6 | 2026-06-10 |
| Proof-of-concept repository on GitHub | stars:3 | 2026-06-10 |
| Proof-of-concept repository on GitHub | stars:1 | 2026-06-13 |
| Proof-of-concept repository on GitHub | stars:2 | 2026-06-13 |
| Proof-of-concept repository on GitHub | stars:0 | 2026-06-18 |
| Proof-of-concept repository on GitHub | stars:0 | 2026-06-20 |
| Proof-of-concept repository on GitHub | stars:0 | 2026-07-05 |
| Proof-of-concept repository on GitHub | stars:1 | 2026-08-21 |
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.
- First PoC-6 d
- Published
- TodayNov 7, 2026+152 d
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 researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- Quang LuongCalif.IO in collaboration with OpenAI Codexfinder
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-42528115 days apartApache HTTP Server: mod_dav shared lock overflow17Monitor
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-789 · Memory Allocation with Excessive Size ValueCVSS vector
CVSS:3.1/AV:N/AC:L/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
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- www.openwall.com/lists/oss-security/2026/06/03/3
- www.openwall.com/lists/oss-security/2026/06/08/16
- lists.debian.org/debian-lts-announce/2026/06/msg00009.html
- access.redhat.com/errata/RHSA-2026:25042
- access.redhat.com/errata/RHSA-2026:25057
- access.redhat.com/errata/RHSA-2026:25090
- access.redhat.com/errata/RHSA-2026:25225
- access.redhat.com/errata/RHSA-2026:27114
- access.redhat.com/errata/RHSA-2026:27200
- access.redhat.com/errata/RHSA-2026:27201
- access.redhat.com/errata/RHSA-2026:36373
- access.redhat.com/errata/RHSA-2026:36831
- access.redhat.com/errata/RHSA-2026:36846
- access.redhat.com/errata/RHSA-2026:50538
- access.redhat.com/errata/RHSA-2026:50572
- access.redhat.com/errata/RHSA-2026:55930
- access.redhat.com/errata/RHSA-2026:55992
- access.redhat.com/security/cve/CVE-2026-49975
- bugzilla.redhat.com/show_bug.cgi?id=2485371
Vendor advisories and official records. Exploit/PoC links are deliberately left out.