CVE-2026-118673
KeePassXC: Out-of-bounds write in browser integration response encryption with oversized database responses
KeePassXC is a cross-platform community-driven port of the Windows application KeePass Password Safe. From 2.3.0 until 2.8.0, KeePassXC browser integration encrypts authorized responses in src/browser/BrowserMessageBuilder.cpp using a fixed 1 MiB output vector even though Botan::Sodium::crypto_box_easy() writes the plaintext length plus crypto_box_MACBYTES. A browser-protocol client that can access the per-user IPC endpoint, has a valid database association, and causes an unlocked database to generate and encrypt a sufficiently large authorized response can trigger a sequential out-of-bounds write before any response is delivered. This issue is fixed in version 2.8.0.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- Low
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
4.1
KeePassXC: Out-of-bounds write in browser integration response encryption with oversized database responses
KeePassXC is a cross-platform community-driven port of the Windows application KeePass Password Safe. From 2.3.0 until 2.8.0, KeePassXC browser integration encrypts authorized responses in src/browser/BrowserMessageBuilder.cpp using a fixed 1 MiB output vector even though Botan::Sodium::crypto_box_easy() writes the plaintext length plus crypto_box_MACBYTES. A browser-protocol client that can access the per-user IPC endpoint, has a valid database association, and causes an unlocked database to generate and encrypt a sufficiently large authorized response can trigger a sequential out-of-bounds write before any response is delivered. This issue is fixed in version 2.8.0.
- Record
CVE-2026-118673- CVSS 4.0
- 4.1 Medium
CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-787
- Updated
- 2026-11-03
EUVDEUVD-2026-113213
4.1
KeePassXC is a cross-platform community-driven port of the Windows application KeePass Password Safe. From 2.3.0 until 2.8.0, KeePassXC browser integration encrypts authorized responses in src/browser/BrowserMessageBuilder.cpp using a fixed 1 MiB output vector even though Botan::Sodium::crypto_box_easy() writes the plaintext length plus crypto_box_MACBYTES. A browser-protocol client that can access the per-user IPC endpoint, has a valid database association, and causes an unlocked database to generate and encrypt a sufficiently large authorized response can trigger a sequential out-of-bounds write before any response is delivered. This issue is fixed in version 2.8.0.
- Record
EUVD-2026-113213- CVSS 4.0
- 4.1 Medium
CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-03
NVD
4.1
KeePassXC is a cross-platform community-driven port of the Windows application KeePass Password Safe. From 2.3.0 until 2.8.0, KeePassXC browser integration encrypts authorized responses in src/browser/BrowserMessageBuilder.cpp using a fixed 1 MiB output vector even though Botan::Sodium::crypto_box_easy() writes the plaintext length plus crypto_box_MACBYTES. A browser-protocol client that can access the per-user IPC endpoint, has a valid database association, and causes an unlocked database to generate and encrypt a sufficiently large authorized response can trigger a sequential out-of-bounds write before any response is delivered. This issue is fixed in version 2.8.0.
- Record
CVE-2026-118673- CVSS 4.0
- 4.1 Medium
CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-787
- Updated
- 2026-11-03
OSV
4.1
KeePassXC: Out-of-bounds write in browser integration response encryption with oversized database responses
KeePassXC is a cross-platform community-driven port of the Windows application KeePass Password Safe. From 2.3.0 until 2.8.0, KeePassXC browser integration encrypts authorized responses in src/browser/BrowserMessageBuilder.cpp using a fixed 1 MiB output vector even though Botan::Sodium::crypto_box_easy() writes the plaintext length plus crypto_box_MACBYTES. A browser-protocol client that can access the per-user IPC endpoint, has a valid database association, and causes an unlocked database to generate and encrypt a sufficiently large authorized response can trigger a sequential out-of-bounds write before any response is delivered. This issue is fixed in version 2.8.0.
- Record
CVE-2026-118673- CVSS 4.0
- 4.1 Medium
CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-787
- Updated
- 2026-11-04
OSVDEBIAN-CVE-2026-118673
4.1
KeePassXC is a cross-platform community-driven port of the Windows application KeePass Password Safe. From 2.3.0 until 2.8.0, KeePassXC browser integration encrypts authorized responses in src/browser/BrowserMessageBuilder.cpp using a fixed 1 MiB output vector even though Botan::Sodium::crypto_box_easy() writes the plaintext length plus crypto_box_MACBYTES. A browser-protocol client that can access the per-user IPC endpoint, has a valid database association, and causes an unlocked database to generate and encrypt a sufficiently large authorized response can trigger a sequential out-of-bounds write before any response is delivered. This issue is fixed in version 2.8.0.
- Record
DEBIAN-CVE-2026-118673- CVSS 4.0
- 4.1 Medium
CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Updated
- 2026-11-04
OSVUBUNTU-CVE-2026-118673
4.1
KeePassXC is a cross-platform community-driven port of the Windows application KeePass Password Safe. From 2.3.0 until 2.8.0, KeePassXC browser integration encrypts authorized responses in src/browser/BrowserMessageBuilder.cpp using a fixed 1 MiB output vector even though Botan::Sodium::crypto_box_easy() writes the plaintext length plus crypto_box_MACBYTES. A browser-protocol client that can access the per-user IPC endpoint, has a valid database association, and causes an unlocked database to generate and encrypt a sufficiently large authorized response can trigger a sequential out-of-bounds write before any response is delivered. This issue is fixed in version 2.8.0.
- Record
UBUNTU-CVE-2026-118673- CVSS 4.0
- 4.1 Medium
CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
keepassxcDebian:12 |
All versions, plus listed versions 2.7.10+dfsg1-12.7.10+dfsg1-22.7.10+dfsg1-2.12.7.4+dfsg.1-22.7.6+dfsg.1-1 Show 7 moreShow less2.7.7+dfsg.1-12.7.7+dfsg.1-1+exp12.7.7+dfsg.1-22.7.7+dfsg.1-32.7.7+dfsg.1-3~exp12.7.9+dfsg1-12.8.0+dfsg1-1 |
None known |
keepassxcDebian:13 |
All versions, plus listed versions 2.7.10+dfsg1-12.7.10+dfsg1-22.7.10+dfsg1-2.12.8.0+dfsg1-1 |
None known |
keepassxcDebian:14 |
before 2.8.0+dfsg1-1, plus listed versions 2.7.10+dfsg1-12.7.10+dfsg1-22.7.10+dfsg1-2.1 |
2.8.0+dfsg1-1 |
keepassxcUbuntu:18.04:LTS |
All versions, plus listed versions 2.2.2-12.2.3+dfsg.1-12.2.4+dfsg.1-12.3.0+dfsg.1-0ubuntu22.3.1+dfsg.1-1 |
None known |
keepassxcUbuntu:20.04:LTS |
All versions, plus listed versions 2.4.3+dfsg.1-12.4.3+dfsg.1-1build1 |
None known |
keepassxcUbuntu:22.04:LTS |
All versions, plus listed versions 2.6.6+dfsg.1-1~exp12.6.6+dfsg.1-1 |
None known |
keepassxcUbuntu:24.04:LTS |
All versions, plus listed versions 2.7.4+dfsg.1-22.7.6+dfsg.1-12.7.6+dfsg.1-1build22.7.6+dfsg.1-1build3 |
None known |
keepassxcUbuntu:26.10 |
All versions, plus listed versions 2.7.10+dfsg1-2ubuntu12.7.10+dfsg1-2.12.7.10+dfsg1-2.1build1 |
None known |
keepassxcUbuntu:26.04:LTS |
All versions, plus listed versions 2.7.10+dfsg1-12.7.10+dfsg1-22.7.10+dfsg1-2ubuntu1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | EUVD, NVD, OSV | |
| facts, references | CVE List | |
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-118673 is a medium vulnerability (CVSS 4.1) in Keepassxc, published October 29, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.11%, the 1st percentile. Fixed in keepassxc 2.8.0+dfsg1-1.
References
github.com/keepassxreboot/keepassxc/security/advisories/GHSA-3448-gh8j-3227
github.com/keepassxreboot/keepassxc/pull/13679
github.com/keepassxreboot/keepassxc/commit/80e68bb4e8b89e383dd96b1bf5de169ca61367aa
github.com/keepassxreboot/keepassxc/releases/tag/2.8.0
github.com/CVEProject/cvelistV5/tree/main/cves/2026/118xxx/CVE-2026-118673.json
nvd.nist.gov/vuln/detail/CVE-2026-118673
security-tracker.debian.org/tracker/CVE-2026-118673
ubuntu.com/security/CVE-2026-118673
cve.org/CVERecord?id=CVE-2026-118673