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NVD / CVE Program· CNA redhat

CVE-2026-35091: Corosync: corosync: denial of service and information disclosure via crafted udp packet

Noroxi assessment

Priority: Monitor (action score 32/100)

  • 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: 0.88% (FIRST EPSS); higher than 59.4% 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: corosync (AlmaLinux:10) 3.1.9-2.el10_1.1, 3.1.10-1.el10_2.1; corosync-vqsim (AlmaLinux:10) 3.1.9-2.el10_1.1, 3.1.10-1.el10_2.1; corosynclib (AlmaLinux:10) 3.1.9-2.el10_1.1, 3.1.10-1.el10_2.1.

Low priority for now. Upgrade to corosync (AlmaLinux:10) 3.1.9-2.el10_1.1, 3.1.10-1.el10_2.1; corosync-vqsim (AlmaLinux:10) 3.1.9-2.el10_1.1, 3.1.10-1.el10_2.1; corosynclib (AlmaLinux:10) 3.1.9-2.el10_1.1, 3.1.10-1.el10_2.1 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

A flaw was found in Corosync. A remote unauthenticated attacker can exploit a wrong return value vulnerability in the Corosync membership commit token sanity check by sending a specially crafted User Datagram Protocol (UDP) packet. This can lead to an out-of-bounds read, causing a denial of service (DoS) and potentially disclosing limited memory contents

HighCVSS 8.2 · v3.1—No exploit Fix available
Published
Apr 1, 2026
Updated
Oct 26, 2026
EPSS
0.8% · 59th percentile

Report tools

JSON

Action score

32

Monitor

Low priority for now.

CVSS
32 / 40 · 8.2 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · redhat
8.2
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • 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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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?

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.

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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
corosynccorosync
redhatopenshift
redhatenterprise linux

Affected versions

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

  • corosync corosyncall versions
  • redhat enterprise linux10.0
  • redhat enterprise linux7.0
  • redhat enterprise linux8.0
  • redhat enterprise linux9.0
  • redhat openshift4.0

Versions reported by the vendor

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

  • Red Hat Red Hat Enterprise Linux 10

    • 0:3.1.9-2.el10_1.1 and laternot affected · rpm
    • 0:3.1.10-1.el10_2.1 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support

    • 0:3.1.9-1.el10_0.2 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support

    • 0:2.4.5-7.el7_9.3 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8

    • 0:3.1.8-1.el8_10.1 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support

    • 0:3.1.0-3.el8_4.2 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

    • 0:3.1.0-3.el8_4.2 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support

    • 0:3.1.5-2.el8_6.1 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.6 Telecommunications Update Service

    • 0:3.1.5-2.el8_6.1 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions

    • 0:3.1.5-2.el8_6.1 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service

    • 0:3.1.7-1.el8_8.1 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions

    • 0:3.1.7-1.el8_8.1 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 9

    • 0:3.1.9-2.el9_7.1 and laternot affected · rpm
    • 0:3.1.10-1.el9_8.1 and laternot affected · rpm

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:10corosyncbefore 3.1.9-2.el10_1.13.1.9-2.el10_1.1
AlmaLinux:10corosyncbefore 3.1.10-1.el10_2.13.1.10-1.el10_2.1
AlmaLinux:10corosync-vqsimbefore 3.1.9-2.el10_1.13.1.9-2.el10_1.1
AlmaLinux:10corosync-vqsimbefore 3.1.10-1.el10_2.13.1.10-1.el10_2.1
AlmaLinux:10corosynclibbefore 3.1.9-2.el10_1.13.1.9-2.el10_1.1
AlmaLinux:10corosynclibbefore 3.1.10-1.el10_2.13.1.10-1.el10_2.1
AlmaLinux:10corosynclib-develbefore 3.1.10-1.el10_2.13.1.10-1.el10_2.1
AlmaLinux:10corosynclib-develbefore 3.1.9-2.el10_1.13.1.9-2.el10_1.1
AlmaLinux:8corosyncbefore 3.1.8-1.el8_10.13.1.8-1.el8_10.1
AlmaLinux:8corosync-vqsimbefore 3.1.8-1.el8_10.13.1.8-1.el8_10.1
AlmaLinux:8corosynclibbefore 3.1.8-1.el8_10.13.1.8-1.el8_10.1
AlmaLinux:8corosynclib-develbefore 3.1.8-1.el8_10.13.1.8-1.el8_10.1
AlmaLinux:8spauseddbefore 3.1.8-1.el8_10.13.1.8-1.el8_10.1
AlmaLinux:9corosyncbefore 3.1.10-1.el9_8.13.1.10-1.el9_8.1
AlmaLinux:9corosyncbefore 3.1.9-2.el9_7.13.1.9-2.el9_7.1
AlmaLinux:9corosync-vqsimbefore 3.1.9-2.el9_7.13.1.9-2.el9_7.1
AlmaLinux:9corosync-vqsimbefore 3.1.10-1.el9_8.13.1.10-1.el9_8.1
AlmaLinux:9corosynclibbefore 3.1.9-2.el9_7.13.1.9-2.el9_7.1
AlmaLinux:9corosynclibbefore 3.1.10-1.el9_8.13.1.10-1.el9_8.1
AlmaLinux:9corosynclib-develbefore 3.1.9-2.el9_7.13.1.9-2.el9_7.1
AlmaLinux:9corosynclib-develbefore 3.1.10-1.el9_8.13.1.10-1.el9_8.1
Debian:12corosyncbefore 3.1.7-1+deb12u23.1.7-1+deb12u2
Debian:13corosyncbefore 3.1.9-2+deb13u13.1.9-2+deb13u1
Debian:14corosyncbefore 3.1.10-23.1.10-2

+96

Same product

corosync: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-30472Corosync through 3.1.9, if encryption is disabled or the attacker knows the encryption key, has a stack-based buffer overflow in orf_token_e
    39Monitor
  • CVE-2018-1084corosync before version 2.4.4 is vulnerable to an integer overflow in exec/totemcrypto.c.
    31Monitor
  • CVE-2026-35092Corosync: corosync: denial of service via integer overflow in join message validation
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2013-0250Jun 6, 2014 · The init_nss_hash function in exec/totemcrypto.c in Corosync 2.0 before 2.3 does not properly initialize the HMAC key, which allows remote a
    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
almalinux:corosync3.1.9-2.el10_1.1 · AlmaLinux:10Package registry (OSV)
almalinux:corosync-vqsim3.1.9-2.el10_1.1 · AlmaLinux:10Package registry (OSV)
almalinux:corosynclib3.1.9-2.el10_1.1 · AlmaLinux:10Package registry (OSV)
almalinux:corosynclib-devel3.1.9-2.el10_1.1 · AlmaLinux:10Package registry (OSV)
almalinux:spausedd3.1.8-1.el8_10.1 · AlmaLinux:8Package registry (OSV)
debian:corosync3.1.7-1+deb12u2 · Debian:12Package registry (OSV)
opensuse:corosync2.4.6-150300.12.16.1 · openSUSE:Leap 15.6Package registry (OSV)
red hat:corosync0:3.1.9-2.el10_1.1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:corosync-debuginfo0:3.1.9-2.el10_1.1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:corosync-debugsource0:3.1.9-2.el10_1.1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:corosync-qdevice0:2.4.5-7.el7_9.3 · Red Hat:enterprise_linux:7::serverPackage registry (OSV)
red hat:corosync-qnetd0:2.4.5-7.el7_9.3 · Red Hat:enterprise_linux:7::serverPackage registry (OSV)
red hat:corosync-vqsim0:3.1.9-2.el10_1.1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:corosync-vqsim-debuginfo0:3.1.9-2.el10_1.1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:corosynclib0:3.1.9-2.el10_1.1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:corosynclib-debuginfo0:3.1.9-2.el10_1.1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:corosynclib-devel0:3.1.9-2.el10_1.1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:spausedd0:3.1.8-1.el8_10.1 · Red Hat:enterprise_linux:8::highavailabilityPackage registry (OSV)
red hat:spausedd-debuginfo0:3.1.8-1.el8_10.1 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
rocky linux:corosync0:3.1.9-2.el10_1.1 · Rocky Linux:10Package registry (OSV)
suse:corosync2.4.6-150300.12.16.1 · SUSE:Linux Enterprise High Availability Extension 15 SP4Package 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.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

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.

No nightly-computed relations.

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
low · data can be read
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
Low
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-253 · Incorrect Check of Function Return Value

CVSS vector

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

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (15 more)

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

All records