CVE-2025-45663: An issue in NetSurf v3.11 causes the application to read uninitialized heap memory when creating a dom_event s

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MEDIUM 6.5REMOTEDOWNGRADE

CVE-2025-45663 is a medium-severity flaw (CVSS 6.5) affecting netsurf. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue in NetSurf v3.11 causes the application to read uninitialized heap memory when creating a dom_event structure.

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 69%)
CISA exploited list	No
Weakness	CWE-244
Published	2025-11-03
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: netsurf-browser

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-11-03 15:15 UTCPublished CVE record published
2026-06-17 09:25 UTCUpdated Record last modified

netsurf-browser netsurf DOWNGRADE

Affected: 3.11

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.11

1. Check installed version

apt-cache policy netsurf || rpm -q netsurf || netsurf --version

2. No fixed release: DOWNGRADE to a release before 3.11 (Debian / Ubuntu)

apt-cache madison netsurf sudo apt install netsurf=<VERSION_BEFORE_3.11> sudo apt-mark hold netsurf

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list netsurf sudo dnf downgrade netsurf-<VERSION_BEFORE_3.11> sudo dnf versionlock add netsurf

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-45663?

netsurf: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-45663 being exploited?

CVE-2025-45663 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-45663 affect?

CVE-2025-45663 affects netsurf. Severity is medium (CVSS 6.5). An issue in NetSurf v3.11 causes the application to read uninitialized heap memory when creating a dom_event structure.

How urgent is CVE-2025-45663?

Priority 40/100. Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-29699 MEDIUM 6.5 DOWNGRADE NetSurf 3.11 is vulnerable to Use After Free in dom_node_set_text_content function.
CVE-2024-51317 MEDIUM 6.5 DOWNGRADE An issue in NetSurf v.3.11 allows a remote attacker to execute arbitrary code via the dom_node_normalize funct

References

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