CVE-2018-5159Firefox Buffer Overflow
An integer overflow can occur in the Skia library due to 32-bit integer use in an array without integer overflow checks, resulting in possible out-of-bounds writes.
Published Jun 11, 2018 · Updated Aug 4, 2026 · Also known as DEBIAN-CVE-2018-5159, UBUNTU-CVE-2018-5159
Key Facts
Patch immediately- CVE-2018-5159 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Firefox (Mozilla), Thunderbird (Mozilla), Thunderbird ESR (Mozilla) and 22 more products.
- It is not listed in any known-exploited vulnerabilities catalog. A public exploit is reported by tracking sources, but no code link is listed yet.
- EPSS estimates a 21% probability of exploitation in the next 30 days.
- Fixed versions are available, including Firefox 0:52.8.0-1.el6_9, Firefox 0:52.8.0-1.el7_5, Firefox 52.8.0-1.0.1.el6_9.
- Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Scores
CVSS v3.1
9.8
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
21%
Higher than 97.4% of all scored CVEs
Exploit maturity
Proof of concept
ATLAS score
47/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Not listed
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Proof of concept
Public exploit code
2
Proof-of-concept links
In-the-wild evidence
0
Reports of active use
Advisories And Exploit References
Description
An integer overflow can occur in the Skia library due to 32-bit integer use in an array without integer overflow checks, resulting in possible out-of-bounds writes. This could lead to a potentially exploitable crash triggerable by web content. This vulnerability affects Thunderbird < 52.8, Thunderbird ESR < 52.8, Firefox < 60, and Firefox ESR < 52.8.
Affected Products
195 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| FirefoxMozilla | >= unspecified | 52.8.0 |
| ThunderbirdMozilla | >= unspecified | 52.8.0 |
| Thunderbird ESRMozilla | >= unspecified | 52.8.0 |
| Ubuntu LinuxCanonical | 14.04, 16.04, 17.10, 18.04 | n/a |
| Debian LinuxDebian | 7.0, 8.0, 9.0 | n/a |
Patched Releases
Firefox
0:52.8.0-1.el6_9, 0:52.8.0-1.el7_5, 52.8.0-1.0.1.el6_9, 52.8.0-1.0.1.el7_5, 60.0-1, 60.0+build2-0ubuntu0.14.04.1, 60.0+build2-0ubuntu0.16.04.1, 60.0+build2-0ubuntu1, 60, 52.8.0
Firefox ESR
52.8, 128.5.1-1.1, 52.8.0esr-1, 52.8.0esr-1~deb7u1, 52.8.0esr-1~deb8u1, 52.8.0esr-1~deb9u1
firefox-esr-branding-upstream
128.5.1-1.1
firefox-esr-translations-common
128.5.1-1.1
firefox-esr-translations-other
128.5.1-1.1
Thunderbird
52.8.0, 0:52.8.0-1.el7_5, 0:52.8.0-2.el6_9, 1:52.8.0-1, 1:52.8.0-1~deb7u1, 1:52.8.0-1~deb8u1, 1:52.8.0-1~deb9u1, 1:52.8.0+build1-0ubuntu0.14.04.1, 1:52.8.0+build1-0ubuntu0.16.04.1, 1:52.8.0+build1-0ubuntu0.18.04.1, 52.8.0-1, 52.8.0-1.0.1.el7_5, 52.8.0-1.amzn2, 52.8.0-2.0.1.el6_9, 52.8
Thunderbird ESR
52.8.0, 52.8
MozillaFirefox
52.8.0-89.1, 52.8.0esr-109.31.2, 52.8.0esr-72.32.1, 52.9.0esr-3.7.12, 68.2.0-109.95.2, 92.0-1.2
MozillaFirefox-branding-upstream
52.8.0-89.1, 92.0-1.2
MozillaFirefox-buildsymbols
52.8.0-89.1
MozillaFirefox-devel
52.8.0-89.1, 52.8.0esr-109.31.2, 52.8.0esr-72.32.1, 52.9.0esr-3.7.12, 68.2.0-109.95.2, 92.0-1.2
MozillaFirefox-translations
52.8.0esr-109.31.2, 52.8.0esr-72.32.1
MozillaFirefox-translations-common
52.8.0-89.1, 52.9.0esr-3.7.12, 68.2.0-109.95.2, 92.0-1.2
MozillaFirefox-translations-other
52.8.0-89.1, 52.9.0esr-3.7.12, 92.0-1.2
MozillaThunderbird
52.8-60.1, 91.1.1-1.1
MozillaThunderbird-buildsymbols
52.8-60.1
MozillaThunderbird-devel
52.8-60.1
MozillaThunderbird-translations-common
52.8-60.1, 91.1.1-1.1
MozillaThunderbird-translations-other
52.8-60.1, 91.1.1-1.1
Timeline
Publicly disclosed
Jun 11, 2018
Last updated
Aug 4, 2026
Weakness Type
- CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
- CWE-190 Integer Overflow or Wraparound
- CWE-787 Out-of-bounds Write
References
- advisorysecurity-tracker.debian.org · CVE-2018-5159
- advisoryubuntu.com · CVE-2018-5159
- advisorycve.org · CVERecord
- advisorymozilla.org · mfsa2018-11
- advisoryRHSA-2018:1414
FAQ
Common Questions.
An integer overflow can occur in the Skia library due to 32-bit integer use in an array without integer overflow checks, resulting in possible out-of-bounds writes.
Affected: Firefox (Mozilla) versions >= unspecified; Thunderbird (Mozilla) versions >= unspecified; Thunderbird ESR (Mozilla) versions >= unspecified, among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
A public exploit is reported by tracking sources, but no code link is listed yet.
Fixed versions are available, including Firefox 0:52.8.0-1.el6_9, Firefox 0:52.8.0-1.el7_5, Firefox 52.8.0-1.0.1.el6_9.
Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
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