CVE-2018-18500
A use-after-free vulnerability can occur while parsing an HTML5 stream in concert with custom HTML elements.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 12.7%, higher than 96% of all known CVEs. Patch or mitigate before the next change window.
Description
A use-after-free vulnerability can occur while parsing an HTML5 stream in concert with custom HTML elements. This results in the stream parser object being freed while still in use, leading to a potentially exploitable crash. This vulnerability affects Thunderbird < 60.5, Firefox ESR < 60.5, and Firefox < 65.
- 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
- 12.66% probability · 96th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- mozilla/firefox · mozilla/firefox esr · mozilla/thunderbird · canonical/ubuntu linux · debian/debian linux · redhat/enterprise linux desktop · redhat/enterprise linux server · redhat/enterprise linux server aus · redhat/enterprise linux server eus · redhat/enterprise linux server tus · redhat/enterprise linux workstation
- Source
- security@mozilla.org
EPSS moved from 11.6% on 21 September 2026 to 12.7% on 27 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
References
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00021.html
- http://www.securityfocus.com/bid/106781Third Party Advisory, VDB Entry
- https://access.redhat.com/errata/RHSA-2019:0218Third Party Advisory
- https://access.redhat.com/errata/RHSA-2019:0219Third Party Advisory
- https://access.redhat.com/errata/RHSA-2019:0269Third Party Advisory
- https://access.redhat.com/errata/RHSA-2019:0270Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2019/01/msg00025.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2019/02/msg00024.htmlMailing List, Third Party Advisory
- https://security.gentoo.org/glsa/201903-04Third Party Advisory
- https://security.gentoo.org/glsa/201904-07
- https://usn.ubuntu.com/3874-1/Third Party Advisory
- https://usn.ubuntu.com/3897-1/Third Party Advisory
- https://www.debian.org/security/2019/dsa-4376Third Party Advisory
- https://www.debian.org/security/2019/dsa-4392Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-01/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-02/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-03/Vendor Advisory
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00021.html
- http://www.securityfocus.com/bid/106781Third Party Advisory, VDB Entry
- https://access.redhat.com/errata/RHSA-2019:0218Third Party Advisory
- https://access.redhat.com/errata/RHSA-2019:0219Third Party Advisory
- https://access.redhat.com/errata/RHSA-2019:0269Third Party Advisory
- https://access.redhat.com/errata/RHSA-2019:0270Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2019/01/msg00025.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2019/02/msg00024.htmlMailing List, Third Party Advisory
- https://security.gentoo.org/glsa/201903-04Third Party Advisory
- https://security.gentoo.org/glsa/201904-07
- https://usn.ubuntu.com/3874-1/Third Party Advisory
- https://usn.ubuntu.com/3897-1/Third Party Advisory
- https://www.debian.org/security/2019/dsa-4376Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.