CVE-2021-36160: mod_proxy_uwsgi out of bound read
Noroxi assessment
Priority: Plan (action score 49/100)
- 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: 63.7% (FIRST EPSS); higher than 99.2% 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.
- Fixed version: httpd (AlmaLinux:8) 2.4.37-47.module_el8.6.0+2935+fb177b09.2, 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma; httpd-devel (AlmaLinux:8) 2.4.37-47.module_el8.6.0+2935+fb177b09.2, 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma; httpd-filesystem (AlmaLinux:8) 2.4.37-47.module_el8.6.0+2935+fb177b09.2, 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma.
- Mentioned 3 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Add it to your regular patch cycle. Upgrade to httpd (AlmaLinux:8) 2.4.37-47.module_el8.6.0+2935+fb177b09.2, 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma; httpd-devel (AlmaLinux:8) 2.4.37-47.module_el8.6.0+2935+fb177b09.2, 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma; httpd-filesystem (AlmaLinux:8) 2.4.37-47.module_el8.6.0+2935+fb177b09.2, 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma 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
A carefully crafted request uri-path can cause mod_proxy_uwsgi to read above the allocated memory and crash (DoS). This issue affects Apache HTTP Server versions 2.4.30 to 2.4.48 (inclusive).
- Published
- Sep 16, 2021
- Updated
- Jun 16, 2026
- EPSS
- 63.7% · 99th percentile
- CWE
- CWE-125
Report tools
Action score
49
Add it to your regular patch cycle.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 19 / 30 · 63.7%
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.
Is Apache HTTP Server on your server exposed to the internet?Run a port scan
Is your version affected? Check itNoroxi 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 |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| netapp | cloud backup | cpe:2.3:a:netapp:cloud_backup |
| netapp | clustered data ontap | cpe:2.3:a:netapp:clustered_data_ontap |
| netapp | storagegrid | cpe:2.3:a:netapp:storagegrid |
| oracle | communications cloud native core network function cloud native environment | cpe:2.3:a:oracle:communications_cloud_native_core_network_function_cloud_native_environment |
| oracle | enterprise manager base platform | cpe:2.3:a:oracle:enterprise_manager_base_platform |
| oracle | http server | cpe:2.3:a:oracle:http_server |
| oracle | instantis enterprisetrack | cpe:2.3:a:oracle:instantis_enterprisetrack |
| oracle | peoplesoft enterprise peopletools | cpe:2.3:a:oracle:peoplesoft_enterprise_peopletools |
| oracle | zfs storage appliance kit | cpe:2.3:a:oracle:zfs_storage_appliance_kit |
and 1 more
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 scanVersions 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
- Apache HTTP Server 2.4 and later · up to and including 2.4.48affected
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- apache http server2.4.30 and later · before 2.4.49
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | httpd | before 2.4.37-47.module_el8.6.0+2935+fb177b09.2 | 2.4.37-47.module_el8.6.0+2935+fb177b09.2 |
| AlmaLinux:8 | httpd | before 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma | 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma |
| AlmaLinux:8 | httpd-devel | before 2.4.37-47.module_el8.6.0+2935+fb177b09.2 | 2.4.37-47.module_el8.6.0+2935+fb177b09.2 |
| AlmaLinux:8 | httpd-devel | before 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma | 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma |
| AlmaLinux:8 | httpd-filesystem | before 2.4.37-47.module_el8.6.0+2935+fb177b09.2 | 2.4.37-47.module_el8.6.0+2935+fb177b09.2 |
| AlmaLinux:8 | httpd-filesystem | before 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma | 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma |
| AlmaLinux:8 | httpd-manual | before 2.4.37-47.module_el8.6.0+2935+fb177b09.2 | 2.4.37-47.module_el8.6.0+2935+fb177b09.2 |
| AlmaLinux:8 | httpd-manual | before 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma | 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma |
| AlmaLinux:8 | httpd-tools | before 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma | 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma |
| AlmaLinux:8 | httpd-tools | before 2.4.37-47.module_el8.6.0+2935+fb177b09.2 | 2.4.37-47.module_el8.6.0+2935+fb177b09.2 |
| AlmaLinux:8 | mod_http2 | before 1.15.7-5.module_el8.6.0+2872+fe0ff7aa | 1.15.7-5.module_el8.6.0+2872+fe0ff7aa |
| AlmaLinux:8 | mod_ldap | before 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma | 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma |
| AlmaLinux:8 | mod_ldap | before 2.4.37-47.module_el8.6.0+2935+fb177b09.2 | 2.4.37-47.module_el8.6.0+2935+fb177b09.2 |
| AlmaLinux:8 | mod_md | before 1:2.0.8-8.module_el8.6.0+2872+fe0ff7aa | 1:2.0.8-8.module_el8.6.0+2872+fe0ff7aa |
| AlmaLinux:8 | mod_proxy_html | before 1:2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma | 1:2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma |
| AlmaLinux:8 | mod_proxy_html | before 1:2.4.37-47.module_el8.6.0+2935+fb177b09.2 | 1:2.4.37-47.module_el8.6.0+2935+fb177b09.2 |
| AlmaLinux:8 | mod_session | before 2.4.37-47.module_el8.6.0+2935+fb177b09.2 | 2.4.37-47.module_el8.6.0+2935+fb177b09.2 |
| AlmaLinux:8 | mod_session | before 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma | 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma |
| AlmaLinux:8 | mod_ssl | before 1:2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma | 1:2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma |
| AlmaLinux:8 | mod_ssl | before 1:2.4.37-47.module_el8.6.0+2935+fb177b09.2 | 1:2.4.37-47.module_el8.6.0+2935+fb177b09.2 |
| Alpine:v3.11 | apache2 | before 2.4.49-r0 | 2.4.49-r0 |
| Debian:10 | apache2 | before 2.4.38-3+deb10u6 | 2.4.38-3+deb10u6 |
| Debian:11 | apache2 | before 2.4.51-1~deb11u1 | 2.4.51-1~deb11u1 |
| Debian:12 | apache2 | before 2.4.49-1 | 2.4.49-1 |
+66
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-2021-31618Jun 15, 2021 · NULL pointer dereference on specially crafted HTTP/2 request46Plan
- ← EarlierCVE-2021-34798Sep 16, 2021 · NULL pointer dereference in httpd core49Plan
- Later →CVE-2021-39275Sep 16, 2021 · ap_escape_quotes buffer overflow51Plan
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 |
|---|---|---|
| almalinux:httpd | 2.4.37-47.module_el8.6.0+2935+fb177b09.2 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:httpd-devel | 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:httpd-filesystem | 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:httpd-manual | 2.4.37-47.module_el8.6.0+2935+fb177b09.2 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:httpd-tools | 2.4.37-47.module_el8.6.0+2935+fb177b09.2 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mod_http2 | 1.15.7-5.module_el8.6.0+2872+fe0ff7aa · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mod_ldap | 2.4.37-47.module_el8.6.0+2935+fb177b09.2 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mod_md | 1:2.0.8-8.module_el8.6.0+2872+fe0ff7aa · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mod_proxy_html | 1:2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mod_session | 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mod_ssl | 1:2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma · AlmaLinux:8 | Package registry (OSV) |
| alpine:apache2 | 2.4.49-r0 · Alpine:v3.11 | Package registry (OSV) |
| debian:apache2 | 2.4.49-1 · Debian:12 | Package registry (OSV) |
| debian:uwsgi | 2.0.14+20161117-3+deb9u4 · Debian:9 | Package registry (OSV) |
| opensuse:apache2 | 2.4.43-lp152.2.21.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| red hat:httpd | 0:2.4.37-47.module+el8.6.0+14529+083145da.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:httpd-debuginfo | 0:2.4.37-47.module+el8.6.0+14529+083145da.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:httpd-debugsource | 0:2.4.37-47.module+el8.6.0+14529+083145da.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:httpd-devel | 0:2.4.37-47.module+el8.6.0+14529+083145da.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:httpd-filesystem | 0:2.4.37-47.module+el8.6.0+14529+083145da.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:httpd-manual | 0:2.4.37-47.module+el8.6.0+14529+083145da.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:httpd-tools | 0:2.4.37-47.module+el8.6.0+14529+083145da.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:httpd-tools-debuginfo | 0:2.4.37-47.module+el8.6.0+14529+083145da.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:mod_http2 | 0:1.15.7-5.module+el8.6.0+13996+01710940 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:mod_http2-debuginfo | 0:1.15.7-5.module+el8.6.0+13996+01710940 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:mod_http2-debugsource | 0:1.15.7-5.module+el8.6.0+13996+01710940 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:mod_ldap | 0:2.4.37-47.module+el8.6.0+14529+083145da.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| rocky linux:httpd | 0:2.4.37-47.module+el8.6.0+823+f143cee1.1 · Rocky Linux:8 | Package registry (OSV) |
| rocky linux:mod_http2 | 0:1.15.7-5.module+el8.6.0+823+f143cee1 · Rocky Linux:8 | Package registry (OSV) |
| rocky linux:mod_md | 1:2.0.8-8.module+el8.5.0+695+1fa8055e · Rocky Linux:8 | Package registry (OSV) |
+1
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.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- LI ZHI XINNSFocus Security Team
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-21-0947 · Nov 25, 2021(Cisco Güvenlik Zafiyeti)
- TR-21-0823 · Oct 11, 2021(Debian Güvenlik Güncellemesi)
- TR-21-0752 · Sep 17, 2021(Apache Güvenlik Zafiyeti)
Not on record for this CVE: EPSS history · patch commit or PR link · variant or chain candidate · public bounty program.
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-125 · Out-of-bounds ReadCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log (1)
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- lists.apache.org/thread.html/r2eb200ac1340f69aa22af61ab34780c531d110437910cb9c0ece3b37%40%3Cbugs.httpd.apache.org%3E
- lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3E
- lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3E
- lists.apache.org/thread.html/r73260f6ba9fb52e43d860905fc90462ba5a814afda2d011f32bbd41c%40%3Cbugs.httpd.apache.org%3E
- lists.apache.org/thread.html/r7f2746e916ed370239bc1a1025e5ebbf345f79df9ea0ea39e44acfbb%40%3Cbugs.httpd.apache.org%3E
- lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3E
- lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3E
- lists.apache.org/thread.html/r94a61a1517133a19dcf40016e87454ea86e355d06a0cec4c778530f3%40%3Cbugs.httpd.apache.org%3E
- lists.apache.org/thread.html/ra1c05a392587bfe34383dffe1213edc425de8d4afc25b7cefab3e781%40%3Cbugs.httpd.apache.org%3E
- lists.apache.org/thread.html/ra87a69d0703d09dc52b86e32b08f8d7327af10acdd5f577a4e82596a%40%3Cbugs.httpd.apache.org%3E
- lists.apache.org/thread.html/rb2341c8786d0f9924f5b666e82d8d170b4804f50a523d750551bef1a%40%3Cbugs.httpd.apache.org%3E
- lists.apache.org/thread.html/re4162adc051c1a0a79e7a24093f3776373e8733abaff57253fef341d%40%3Ccvs.httpd.apache.org%3E
- lists.apache.org/thread.html/ree7519d71415ecdd170ff1889cab552d71758d2ba2904a17ded21a70%40%3Ccvs.httpd.apache.org%3E
- lists.debian.org/debian-lts-announce/2021/09/msg00016.html
- lists.debian.org/debian-lts-announce/2021/10/msg00016.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/
- security.gentoo.org/glsa/202208-20
- security.netapp.com/advisory/ntap-20211008-0004/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.