CVE-2017-7793
A use-after-free vulnerability can occur in the Fetch API when the worker or the associated window are freed when still in use, resulting in a potentially exploitable crash.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (2.27%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
A use-after-free vulnerability can occur in the Fetch API when the worker or the associated window are freed when still in use, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.
- CVSS 3.0
- 9.8 CRITICALCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 2.27% probability · 83th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- debian/debian linux · redhat/enterprise linux · redhat/enterprise linux desktop · redhat/enterprise linux server · redhat/enterprise linux server aus · redhat/enterprise linux server eus · redhat/enterprise linux workstation · mozilla/thunderbird · mozilla/firefox
- Source
- security@mozilla.org
EPSS 2.3% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.securityfocus.com/bid/101055Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1039465Third Party Advisory, VDB Entry
- https://access.redhat.com/errata/RHSA-2017:2831Third Party Advisory
- https://access.redhat.com/errata/RHSA-2017:2885Third Party Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1371889Issue Tracking, Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2017/11/msg00000.htmlThird Party Advisory
- https://security.gentoo.org/glsa/201803-14Third Party Advisory
- https://www.debian.org/security/2017/dsa-3987Third Party Advisory
- https://www.debian.org/security/2017/dsa-4014Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-21/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-22/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-23/Vendor Advisory
- http://www.securityfocus.com/bid/101055Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1039465Third Party Advisory, VDB Entry
- https://access.redhat.com/errata/RHSA-2017:2831Third Party Advisory
- https://access.redhat.com/errata/RHSA-2017:2885Third Party Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1371889Issue Tracking, Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2017/11/msg00000.htmlThird Party Advisory
- https://security.gentoo.org/glsa/201803-14Third Party Advisory
- https://www.debian.org/security/2017/dsa-3987Third Party Advisory
- https://www.debian.org/security/2017/dsa-4014Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-21/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-22/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-23/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.