What is the CVSS score of CVE-2026-0818?

CVE-2026-0818 has a CVSS 3.1 base score of 4.3 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N. EPSS exploitation probability: 0.0%.

Which versions of Mozilla are affected by CVE-2026-0818?

CVE-2026-0818 presents moderate security risk rated CVSS 4.3. Exploitation could compromise the security of affected deployments.. A patch is available.

How to fix or mitigate CVE-2026-0818?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.

Mozilla CVE-2026-0818

MEDIUM

Improper Encoding or Escaping of Output (CWE-116)

2026-01-28 security@mozilla.org

Mozilla Information Disclosure

4.3

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

4.3 MEDIUM

AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

SUSE

MEDIUM

qualitative

Primary rating from NVD.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Lifecycle Timeline

Patch released

Apr 09, 2026 - 14:30 nvd

Patch available

Analysis Generated

Mar 12, 2026 - 21:54 vuln.today

CVE Published

Jan 28, 2026 - 08:16 nvd

MEDIUM 4.3

DescriptionCVE.org

When a user explicitly requested Thunderbird to decrypt an inline OpenPGP message that was embedded in a text section of an email that was formatted and styled with HTML and CSS, then the decrypted contents were rendered in a context in which the CSS styles from the outer messages were active. If the user had additionally allowed loading of the remote content referenced by the outer email message, and the email was crafted by the sender using a combination of CSS rules and fonts and animations, then it was possible to extract the secret contents of the email. This vulnerability affects Thunderbird < 147.0.1 and Thunderbird < 140.7.1.

AnalysisAI

Thunderbird's inline OpenPGP message decryption can leak secret email contents through CSS style injection when remote content loading is enabled, allowing attackers to extract decrypted plaintext via crafted email formatting. This affects Thunderbird versions before 147.0.1 and 140.7.1, requiring user interaction to trigger the vulnerability. No patch is currently available.

Technical ContextAI

Classified as CWE-116 (Improper Encoding or Escaping of Output). Affects Thunderbird. When a user explicitly requested Thunderbird to decrypt an inline OpenPGP message that was embedded in a text section of an email that was formatted and styled with HTML and CSS, then the decrypted contents were rendered in a context in which the CSS styles from the outer messages were active. If the user had additionally allowed loading of the remote content referenced by the outer email message, and the email was crafted by the sender using a combination of CSS rules and fonts and animations,

RemediationAI

Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.

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Vendor StatusVendor

SUSE

Severity: Medium

Product	Status
SUSE Linux Enterprise Desktop 15 SP7 SUSE Linux Enterprise Server 15 SP7 SUSE Linux Enterprise Server for SAP Applications 15 SP7 SUSE Linux Enterprise Workstation Extension 15 SP7	Fixed
SUSE Linux Enterprise Module for Package Hub 15 SP7	Fixed
openSUSE Leap 15.6	Fixed
openSUSE Leap 16.0	Fixed
openSUSE Tumbleweed	Fixed

CVE-2026-0818 vulnerability details – vuln.today

Back

SUSE Linux Enterprise Desktop 15 SP7	Fixed
SUSE Linux Enterprise Module for Package Hub 15 SP7	Fixed
SUSE Linux Enterprise Server 15 SP7	Fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP7	Fixed
SUSE Linux Enterprise Workstation Extension 15 SP7	Fixed
openSUSE Leap 15.6	Fixed
SUSE Linux Enterprise Server 15 SP4	Fixed
SUSE Linux Enterprise Server 15 SP5	Fixed
SUSE Linux Enterprise Server 15 SP6	Fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP6	Fixed
SUSE Linux Enterprise Desktop 15 SP2	Fixed
SUSE Linux Enterprise Desktop 15 SP3	Fixed
SUSE Linux Enterprise Desktop 15 SP4	Fixed
SUSE Linux Enterprise Desktop 15 SP5	Fixed
SUSE Linux Enterprise Desktop 15 SP6	Fixed
SUSE Linux Enterprise Module for Package Hub 15 SP3	Fixed
SUSE Linux Enterprise Module for Package Hub 15 SP4	Fixed
SUSE Linux Enterprise Module for Package Hub 15 SP5	Fixed
SUSE Linux Enterprise Module for Package Hub 15 SP6	Fixed
SUSE Linux Enterprise Server 15 SP2	Fixed
SUSE Linux Enterprise Server 15 SP3	Fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP2	Fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP3	Fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP4	Fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP5	Fixed
SUSE Linux Enterprise Workstation Extension 15 SP2	Fixed
SUSE Linux Enterprise Workstation Extension 15 SP3	Fixed
SUSE Linux Enterprise Workstation Extension 15 SP4	Fixed
SUSE Linux Enterprise Workstation Extension 15 SP5	Fixed
SUSE Linux Enterprise Workstation Extension 15 SP6	Fixed
openSUSE Leap 15.3	Fixed
openSUSE Leap 15.4	Fixed
openSUSE Leap 15.5	Fixed

Mozilla CVE-2026-0818

Severity by source

CVSS VectorNVD

Lifecycle Timeline

DescriptionCVE.org

AnalysisAI

Technical ContextAI

RemediationAI

More in Mozilla

Same weakness CWE-116 – Improper Encoding or Escaping of Output

Same technique Information Disclosure

Vendor StatusVendor

SUSE

Share

External POC / Exploit Code