Skip to main content

Boteraser | Website and Server Security Solutions

🛡️ CVE-2026-9076 on Ubuntu — edk2

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Issue summary: When CMS password-based decryption (RFC 3211 / PWRI key unwrap) processes attacker-supplied CMS data, an attacker-chosen stream-mode KEK cipher can trigger a heap out-of-bounds read in kek_unwrap_key(). Impact summary: A heap buffer over-read may trigger a crash which leads to Denial of Service for an application if the input buffer ends at a memory page boundary and the following page is unmapped. There is no information disclosure as the over-read bytes are not revealed to the attacker. The key unwrapping function performs a check-byte test as specified in the RFC that reads 7 bytes from a heap allocation that is based on the wrapped key length from the message. There is a minimum length check based on the block length of the wrapping cipher. However the cipher is selected from an OID carried in the attacker's PWRI keyEncryptionAlgorithm with no requirement that the cipher be a block cipher. When an attacker selects a stream-mode cipher the guard will be ineffective and the allocated buffer containing the unwrapped key can be too small to fit the check-bytes specified in the RFC and a buffer over-read can happen. Applications calling CMS_decrypt() or CMS_decrypt_set1_password() (equivalently openssl cms -decrypt -pwri_password ...) on untrusted CMS data are vulnerable to this issue. No password knowledge is required: the over-read happens during the unwrap attempt before any authentication succeeds. The over-read is limited to a few bytes and is not written to output, so there is no information disclosure. Triggering a crash requires the allocation to border unmapped memory, which is unlikely with the normal allocator. The FIPS modules are not affected by this issue.

Distribution advisory

This page covers CVE-2026-9076 as tracked by Ubuntu, for the package edk2. The fix is available in version 3.5.5-1ubuntu3.2; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

UBUNTU-CVE-2026-9076 is classified as CWE-125: Out-of-bounds Read. The code reads past the limits of a buffer, exposing adjacent memory contents or crashing the process.

Affected software

UBUNTU-CVE-2026-9076 is recorded against 5 packages.

  • edk2
  • nodejs
  • openssl (fixed in 3.5.5-1ubuntu3.2)
  • openssl-fips
  • openssl1.0 (fixed in 1.0.2n-1ubuntu5.13+esm5)

Timeline and source

Published on 9 June 2026 and last revised on 8 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
openssl-library.org (Report)
ubuntu.com (Advisory)
ubuntu.com (Advisory)

Other advisories for this package

edk2 has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-125: Out-of-bounds Read) in other software:

CVE-2026-9076 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-06-09
Updated 2026-08-20
Modified 2026-07-08
Fix URL N/A

Affected Packages

Software From version Fixed in
edk2 — —
nodejs — —
openssl — 3.5.5-1ubuntu3.2
openssl-fips — —
openssl1.0 — 1.0.2n-1ubuntu5.13+esm5

Similar Threats

Site Security Check

Is edk2 part of your stack?

UBUNTU-CVE-2026-9076 is rated CVSS 7.5 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

Scan My Site Free →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

Browse related advisories

All advisoriesUbuntuUbuntu 2026
✓