CVE-2025-5271
Devtools' preview ignored CSP headers
6.5 MediumFix available
Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability was fixed in Firefox 139 and Thunderbird 139.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
0.31%Up 0.3 points since May 28, 2025
What each source reports
CVE List Score used
Devtools' preview ignored CSP headers
Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability was fixed in Firefox 139 and Thunderbird 139.
- Record
CVE-2025-5271- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-116
- Updated
- 2026-11-02
EUVDEUVD-2025-18105
Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability was fixed in Firefox 139 and Thunderbird 139.
- Record
EUVD-2025-18105- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-jc7v-r8h6-xr5c
Previewing a response in Devtools ignored CSP headers, which could have allowed content injection...
Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability affects Firefox < 139.
- Record
GHSA-jc7v-r8h6-xr5c- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-116
- Updated
- 2026-11-02
NVD
Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability was fixed in Firefox 139 and Thunderbird 139.
- Record
CVE-2025-5271- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-116
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2025-5271
Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability was fixed in Firefox 139 and Thunderbird 139.
- Record
UBUNTU-CVE-2025-5271- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Updated
- 2026-11-02
OSVopenSUSE-SU-2025:15196-1 No score
MozillaFirefox-139.0.1-1.1 on GA media
These are all security issues fixed in the MozillaFirefox-139.0.1-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2025:15196-1- Updated
- 2026-11-02
OSVopenSUSE-SU-2026:11373-1 No score
firefox-esr-153.0-1.1 on GA media
These are all security issues fixed in the firefox-esr-153.0-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:11373-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
mozjs52Ubuntu:18.04:LTS |
All versions, plus listed versions 52.3.1-0ubuntu352.3.1-7fakesync152.8.1-0ubuntu0.18.04.152.9.1-0ubuntu0.18.04.1 |
None known |
mozjs38Ubuntu:18.04:LTS |
All versions, plus listed versions 38.8.0~repack1-0ubuntu138.8.0~repack1-0ubuntu338.8.0~repack1-0ubuntu4 |
None known |
mozjs68Ubuntu:20.04:LTS |
All versions, plus listed versions 68.5.0-1~fakesync68.5.0-2~fakesync68.6.0-168.6.0-1ubuntu1 |
None known |
mozjs52Ubuntu:20.04:LTS |
All versions, plus listed versions 52.9.1-1build152.9.1-1ubuntu3 |
None known |
mozjs102Ubuntu:22.04:LTS |
All versions, plus listed versions 102.11.0-0ubuntu0.22.04.1102.12.0-0ubuntu0.22.04.1102.13.0-0ubuntu0.22.04.1102.15.1-0ubuntu0.22.04.1 |
None known |
mozjs78Ubuntu:22.04:LTS |
All versions, plus listed versions 78.13.0-178.15.0-278.15.0-4ubuntu1 |
None known |
mozjs91Ubuntu:22.04:LTS |
All versions, plus listed versions 91.5.1-0ubuntu191.6.0-191.6.0-291.7.0-291.10.0-0ubuntu1 |
None known |
thunderbirdUbuntu:22.04:LTS |
before 1:140.7.1+build1-0ubuntu0.22.04.1, plus listed versions 1:91.1.2+build1-0ubuntu11:91.3.0+build2-0ubuntu11:91.3.1+build1-0ubuntu11:91.3.2+build1-0ubuntu11:91.4.0+build1.1-0ubuntu1 Show 33 moreShow less1:91.4.0+build2-0ubuntu11:91.5.0+build1-0ubuntu11:91.5.1+build1-0ubuntu11:91.6.1+build1-0ubuntu11:91.7.0+build1-0ubuntu11:91.7.0+build2-0ubuntu11:91.8.0+build2-0ubuntu11:91.9.1+build1-0ubuntu0.22.04.11:91.11.0+build2-0ubuntu0.22.04.11:102.2.2+build1-0ubuntu0.22.04.11:102.4.2+build2-0ubuntu0.22.04.11:102.7.1+build2-0ubuntu0.22.04.11:102.8.0+build2-0ubuntu0.22.04.11:102.9.0+build1-0ubuntu0.22.04.11:102.10.0+build2-0ubuntu0.22.04.11:102.11.0+build1-0ubuntu0.22.04.11:102.13.0+build1-0ubuntu0.22.04.11:102.15.0+build1-0ubuntu0.22.04.11:102.15.1+build1-0ubuntu0.22.04.11:115.3.1+build1-0ubuntu0.22.04.21:115.4.1+build1-0ubuntu0.22.04.11:115.5.0+build1-0ubuntu0.22.04.11:115.6.0+build2-0ubuntu0.22.04.11:115.8.1+build1-0ubuntu0.22.04.11:115.9.0+build1-0ubuntu0.22.04.11:115.10.1+build1-0ubuntu0.22.04.11:115.11.0+build2-0ubuntu0.22.04.11:115.12.0+build3-0ubuntu0.22.04.11:115.13.0+build5-0ubuntu0.22.04.11:115.15.0+build1-0ubuntu0.22.04.11:115.16.0+build2-0ubuntu0.22.04.11:115.18.0+build1-0ubuntu0.22.04.11:128.12.0+build1-0ubuntu0.22.04.1 |
1:140.7.1+build1-0ubuntu0.22.04.1 |
mozjs102Ubuntu:24.04:LTS |
All versions, plus listed versions 102.15.1-1102.15.1-3ubuntu2 |
None known |
mozjs115Ubuntu:24.04:LTS |
All versions, plus listed versions 115.3.0-0ubuntu1115.4.0-2115.5.0-1115.6.0-1115.7.0-4 Show 4 moreShow less115.8.0-1115.9.0-1115.9.0-1build1115.10.0-1 |
None known |
MozillaFirefoxopenSUSE:Tumbleweed From an advisory covering 9 CVEs |
before 139.0.1-1.1 | 139.0.1-1.1 |
firefox-esropenSUSE:Tumbleweed From an advisory covering 228 CVEs |
before 153.0-1.1 | 153.0-1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-5271 is a medium vulnerability (CVSS 6.5) in Mozilla Firefox, published May 27, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.31%, the 23rd percentile. Fixed in thunderbird 1:140.7.1+build1-0ubuntu0.22.04.1.
References
bugzilla.mozilla.org/show_bug.cgi?id=1920348
mozilla.org/security/advisories/mfsa2025-42
nvd.nist.gov/vuln/detail/CVE-2025-5271
github.com/advisories/GHSA-jc7v-r8h6-xr5c
ubuntu.com/security/CVE-2025-5271
Show 194 moreShow less
cve.org/CVERecord?id=CVE-2025-5271
suse.com/security/cve/CVE-2025-5263
This page doesn't list everything
Left out here: 43 references. The JSON record has them.