CVE-2026-75805: NULL Pointer Dereference in CMP Client Revocation Response Handling
Noroxi assessment
Priority: Monitor (action score 21/100)
- 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: 0.32% (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: OpenSSL OpenSSL 3.0.23, 3.4.8, 3.5.9; azl3 edk2 20240524git3e722403cd16-20 on Azure Linux 3.0 20240524git3e722403cd16-21; azl3 openssl 3.3.7-6 on Azure Linux 3.0 3.3.7-7.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to OpenSSL OpenSSL 3.0.23, 3.4.8, 3.5.9; azl3 edk2 20240524git3e722403cd16-20 on Azure Linux 3.0 20240524git3e722403cd16-21; azl3 openssl 3.3.7-6 on Azure Linux 3.0 3.3.7-7 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
Issue summary: A CMP client that requests certificate revocation on the basis of a PKCS#10 CSR may dereference a NULL pointer and terminate abnormally when processing a crafted revocation response. Impact summary: The NULL pointer dereference happens on a read which leads to a crash and a Denial of Service for the affected client application. CWE: CWE-476: NULL-pointer dereference Description: A CMP client revoking a certificate has to tell the server which certificate to revoke, and may do so by supplying a PKCS#10 CSR instead of the certificate itself or its issuer name and serial number. This is 'openssl cmp -cmd rr -csr <file>' on the command line, or OSSL_CMP_exec_RR_ses() with the certificate supplied via OSSL_CMP_CTX_set1_p10CSR() through the API. A CSR does not contain the issuer name and serial number of the certificate, so the client does not send them. A server may optionally name the certificate it revoked in its response, and the client then compares that name against what it sent. Having sent neither an issuer name nor a serial number, it has nothing to compare against, and a server returning a specially crafted name causes the client to read from a NULL pointer and crash. The revocation response is checked for valid message protection before the affected code is reached, so an attacker must be a malicious or compromised CMP server, or a man-in-the-middle in possession of the secret used for message protection. Clients that identify the certificate to be revoked by a certificate or by issuer and serial number rather than by a PKCS#10 CSR are not affected. FIPS impact: no No FIPS modules are affected by this issue, as the CMP protocol implementation is outside the OpenSSL FIPS module boundary.
- Published
- Sep 29, 2026
- Updated
- Oct 8, 2026
- EPSS
- 0.3% · 25th percentile
- CWE
- CWE-476
Report tools
Action score
21
Monitor
Low priority for now.
- CVSS
- 21 / 40 · 5.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
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.
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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.
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 |
|---|---|---|
| openssl | openssl | cpe:2.3:a:openssl:openssl |
Check your server's TLS configuration
The OpenSSL version can't be seen from outside; the free SSL checker tests your certificate, enabled TLS versions and weak ciphers. Confirm the version on your server with the package manager.
Run the SSL checkAffected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- openssl openssl3.0.0 and later · before 3.0.23
- openssl openssl3.4.0 and later · before 3.4.8
- openssl openssl3.5.0 and later · before 3.5.9
- openssl openssl3.6.0 and later · before 3.6.5
- openssl openssl4.0.0 and later · before 4.0.3
Versions reported by the vendor
Affected version ranges reported by the assigning authority (openssl). Independent of NVD's CPE analysis and usually ahead of it.
OpenSSL OpenSSL
- 4.0.0 and later · before 4.0.3affected · semver
- 3.6.0 and later · before 3.6.5affected · semver
- 3.5.0 and later · before 3.5.9affected · semver
- 3.4.0 and later · before 3.4.8affected · semver
- 3.0.0 and later · before 3.0.23affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.21 | openssl | from 3.0.0 · before 3.3.7-r2 | 3.3.7-r2 |
| Debian:12 | openssl | before 3.0.22-1~deb12u2 | 3.0.22-1~deb12u2 |
| Debian:13 | openssl | before 3.5.7-1~deb13u3 | 3.5.7-1~deb13u3 |
| Debian:14 | openssl | before 3.6.5-1 | 3.6.5-1 |
| openSUSE:Leap 16.0 | openssl-3 | before 3.5.0-160000.11.1 | 3.5.0-160000.11.1 |
| Red Hat:hummingbird:1 | openssl | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl-config-fips | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl-devel | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl-devel-engine | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl-fips-provider-upstream | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl-libs | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl-perl | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl3 | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl3-devel | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl3-devel-engine | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl3-libs | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | openssl-3 | before 3.0.8-150500.5.80.1 | 3.0.8-150500.5.80.1 |
| SUSE:Linux Enterprise Micro 5.3 | openssl-3 | before 3.0.8-150400.4.101.1 | 3.0.8-150400.4.101.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | openssl-3 | before 3.5.0-150700.5.53.2 | 3.5.0-150700.5.53.2 |
| SUSE:Linux Enterprise Server 15 SP6-LTSS | openssl-3 | before 3.1.4-150600.5.67.1 | 3.1.4-150600.5.67.1 |
| SUSE:Linux Micro 6.0 | openssl-3 | before 3.1.4-159998.1.1 | 3.1.4-159998.1.1 |
| SUSE:Linux Micro 6.1 | openssl-3 | before 3.1.4-slfo.1.1_14.1 | 3.1.4-slfo.1.1_14.1 |
| SUSE:Linux Micro 6.2 | openssl-3 | before 3.5.0-160000.11.1 | 3.5.0-160000.11.1 |
Same product
openssl: all recordsOther highest-scoring records for the same primary product.
- CVE-2014-0160The (1) TLS and (2) DTLS implementations in OpenSSL 1.0.1 before 1.0.1g do not properly handle Heartbeat Extension packets, which allows remKEV90Now
- CVE-2021-3711SM2 Decryption Buffer Overflow65This week
- CVE-2003-0545Double free vulnerability in OpenSSL 0.9.7 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code 65This week
Published before and after this one in the same product
- ← EarlierCVE-2026-72897Sep 29, 2026 · Out-of-Bounds Access After SSL_set_SSL_CTX() During a Handshake30Monitor
- ← EarlierCVE-2026-75804Sep 29, 2026 · QUIC Connection-Level Flow Control is Not Enforced for Streams21Monitor
- Later →CVE-2026-75806Sep 29, 2026 · Unauthenticated and Undersized DTLS 1.2 AEAD Record Causes DoS21Monitor
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 |
|---|---|---|
| OpenSSL OpenSSL | 3.0.23 | Vendor (CNA) |
| OpenSSL OpenSSL | 3.4.8 | Vendor (CNA) |
| OpenSSL OpenSSL | 3.5.9 | Vendor (CNA) |
| OpenSSL OpenSSL | 3.6.5 | Vendor (CNA) |
| OpenSSL OpenSSL | 4.0.3 | Vendor (CNA) |
| azl3 edk2 20240524git3e722403cd16-20 on Azure Linux 3.0 | 20240524git3e722403cd16-21 · Release Notes | Microsoft (MSRC) |
| azl3 openssl 3.3.7-6 on Azure Linux 3.0 | 3.3.7-7 · Release Notes | Microsoft (MSRC) |
| alpine:openssl | 3.3.7-r2 · Alpine:v3.21 | Package registry (OSV) |
| debian:openssl | 3.0.22-1~deb12u2 · Debian:12 | Package registry (OSV) |
| debian:openssl | 3.5.7-1~deb13u3 · Debian:13 | Package registry (OSV) |
| opensuse:openssl-3 | 3.5.0-160000.11.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| red hat:openssl | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl-config-fips | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl-devel | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl-devel-engine | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl-fips-provider-upstream | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl-libs | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl-perl | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl3 | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl3-devel | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl3-devel-engine | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl3-libs | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| suse:openssl-3 | 3.0.8-150500.5.80.1 · SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | Package registry (OSV) |
| suse:openssl-3 | 3.1.4-159998.1.1 · SUSE:Linux Micro 6.0 | Package 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.
- Published
- Fix recordedsame day
- TodayNov 7, 2026+39 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.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- Bhabani Sankar Dasreporter
- Norbert Pocsremediation developer
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-1445735 days apartRPK Server Signature Algorithm Selection Can Dereference a Missing Certificate30Monitor
- CVE-2026-6307635 days apartInvalid Pointer Dereference in CMP Server via Crafted protectionAlg30Monitor
- CVE-2026-42764112 days apartNULL Pointer Dereference in QUIC Server Initial Packet Handling30Monitor
- CVE-2026-42765112 days apartNULL Dereference in Certificate Verification with OCSP Checking30Monitor
- CVE-2026-28388175 days apartNULL Pointer Dereference When Processing a Delta CRL30Monitor
- CVE-2026-28390175 days apartPossible NULL Dereference When Processing CMS KeyTransportRecipientInfo30Monitor
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.
- TR-26-1218 · Sep 30, 2026(OpenSSL Güvenlik Zafiyeti)
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
- low · 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
- Low
Weakness class (CWE)
CWE-476 · NULL Pointer DereferenceCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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
- Exploit maturity— → none
- Fix✗ → ✓
- CVSS— → 5.3
- Severity— → medium
- SSVC exploitation— → none
For records you follow, these changes also arrive as notifications. →
References
Show all references (4 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.