CVE-2025-10536

Sensitive response disclosure via ignored no-store directive

Published Sep 16, 2025 · Updated Sep 16, 2025

Information disclosure in Firefox and Thunderbird before 143 and their ESR lines before 140.3 allows local users to read cached data. nsHttpResponseHead::ParseHeaderLine_locked reparses only the latest Cache-Control header instead of the merged value, so an earlier no-store directive is lost and the response is written to disk. Exploitation requires local access to the application profile or cache; the entry is not reused, but sensitive response data can persist across restarts.

CVSS severity6.2
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Firefox and Thunderbird before 143 and their ESR lines before 140.3 allows local users to read cached data. nsHttpResponseHead::ParseHeaderLine_locked reparses only the latest Cache-Control header instead of the merged value, so an earlier no-store directive is lost and the response is written to disk. Exploitation requires local access to the application profile or cache; the entry is not reused, but sensitive response data can persist across restarts.

The record

CVE
CVE-2025-10536
Published
Sep 16, 2025
Updated
Sep 16, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-200, T1005
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <143

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <143
Mozilla · Thunderbirdversion=unspecified <140.3; version=unspecified <143
Mozilla · Firefox ESRversion=unspecified <140.3

Published CVSS scores

6.2CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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