FirefoxWeb browser · Mozilla
CVE-2024-4774
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe `ShmemCharMapHashEntry()` code was susceptible to potentially undefined behavior by bypassing the move semantics for one of its data members. This vulnerability affects Firefox < 126.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA code vulnerability in Firefox's ShmemCharMapHashEntry() function allows undefined behavior by improperly bypassing move semantics for a data member. This could potentially lead to memory corruption or unexpected behavior when handling shared memory character map entries. The issue affects Firefox versions prior to 126.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
FirefoxWeb browser
< 126.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Check if Firefox is installedRun 'which firefox' on Linux/macOS, check Start Menu on Windows, or run 'firefox --version' to see if the command is recognizedAffected if Firefox is not found on the system - the user is not affected since the product is not in use
-
Retrieve the installed Firefox version numberRun 'firefox --version' from command line, or open Firefox and navigate to 'about:firefox' in the address barAffected if The command fails or returns no version - the version could not be determined
-
Compare the installed version against the affected rangeCheck if the version number is below 126.0. For example, versions like 125.0, 124.0, 115.x ESR, etc. are all prior to 126Affected if The installed version is any release prior to 126.0 (for example 125.x, 124.x, 115.x ESR) - the environment is affected by this vulnerability
A user is affected if they have Mozilla Firefox installed with a version number less than 126.0, as only versions prior to 126.0 contain the vulnerability in the ShmemCharMapHashEntry() function.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped126.0
Upgrade Firefox to version 126 or later to remediate this vulnerability.
Firefox 126.0
- 1. Open Firefox and navigate to Help > About Firefox to check the current version
- 2. If the version is below 126.0, select the option to update Firefox
- 3. Alternatively, download Firefox 126.0 or later from the official Mozilla website at www.mozilla.org
- 4. Restart Firefox after the update completes
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation1.0 h
- Testing1.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-4774 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2024-4774 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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