CVE-2018-12393: canonical ubuntu_linux Integer Overflow or Wraparound
Vulnerability summary
CVE-2018-12393 is a high (CVSS 7.5) Integer Overflow or Wraparound vulnerability in canonical ubuntu_linux. EPSS estimates a 3.92% chance of exploitation in the next 30 days, higher than 90.3% of scored vulnerabilities.
Severe, CVSS 7.5 (NVD); no exploitation reported by the 5 checked sources; EPSS 4% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 21 · Related 11Timeline
- 28-02-2019PublishedVulnerability first disclosed.
- 05-08-2024Last modifiedVulnerability information updated.
Description
A potential vulnerability was found in 32-bit builds where an integer overflow during the conversion of scripts to an internal UTF-16 representation could result in allocating a buffer too small for the conversion. This leads to a possible out-of-bounds write. *Note: 64-bit builds are not vulnerable to this issue.*. This vulnerability affects Firefox < 63, Firefox ESR < 60.3, and Thunderbird < 60.3.
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
3.92%
Chance of exploitation in the next 30 days
Percentile
90%
Versus all other CVEs
30-day change
No change 0.00 pp
From 3.92% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
- CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.
Affected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Redhat6 products
- enterprise_linux_desktop6.0 | 7.0
- enterprise_linux_server6.0 | 7.0
- enterprise_linux_server_aus7.6
- enterprise_linux_server_eus7.6
- enterprise_linux_server_tus7.6
Ubuntu4 products
- firefox< 63.0+build2-0ubuntu0.14.04.2 | < 63.0+build2-0ubuntu0.16.04.2 | < 63.0+build2-0ubuntu0.18.04.2
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- thunderbird< 1:60.4.0+build2-0ubuntu0.14.04.1 | < 1:60.4.0+build2-0ubuntu0.16.04.1 | < 1:60.4.0+build2-0ubuntu0.18.04.1
Debian3 products
- firefox-esr< 60.3.0esr-1
- thunderbird< 1:60.3.0-1
- debian_linuxEOL8.0 | 9.0
Mozilla3 products
- firefox≥ unspecified, < 63 | < 63.0
- firefox esr≥ unspecified, < 60.3 | < 60.3
- thunderbird≥ unspecified, < 60.3 | < 60.3
Canonical1 product
- ubuntu_linuxEOL14.04 | 16.04 | 18.04 | 18.10
5 vendors · 17 products
References
27 links
- lists.debian.org/debian-lts-announce/2018/11/msg00011.htmlMailing ListX Refsource MLISTThird Party Advisory
Show all 27 references
- bugzilla.mozilla.org/show_bug.cgi?id=1495011X Refsource CONFIRMIssue TrackingPermissions RequiredVendor Advisory
- lists.debian.org/debian-lts-announce/2018/11/msg00008.htmlMailing ListX Refsource MLISTThird Party Advisory