Distribution advisory
This page covers CVE-2025-0243 as tracked by Debian, for the package firefox-esr. The fix is available in version 128.6.0esr-1; earlier versions remain affected.
How this vulnerability can be exploited
This issue can be reached with local access to the system, 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 low, integrity low, availability none.
CVSS metrics in full
The score comes from this vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- Attack vector: Local — a local account, shell or session on the host is needed.
- 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: Low — limited, and the attacker does not choose what is affected.
- Integrity impact: Low — limited, and the attacker does not choose what is affected.
- Availability impact: None.
Weakness class
DEBIAN-CVE-2025-0243 is classified as CWE-787: Out-of-bounds Write. Data is written past the end or before the start of a buffer, corrupting whatever is stored there.
Affected software
DEBIAN-CVE-2025-0243 is recorded against 2 packages.
- firefox-esr (fixed in 128.6.0esr-1)
- thunderbird (fixed in 1:128.6.0esr-1)
Timeline and source
Published on 7 January 2025 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.
References
security-tracker.debian.org (Advisory)
Other advisories for this package
firefox-esr 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-787: Out-of-bounds Write) in other software:
