CVE-2020-14315: A memory corruption vulnerability is present in bspatch as shipped in Colin Percival’s bsdiff tools version 4.

This week

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2020-14315 is a critical-severity flaw (CVSS 9.8) affecting bsdiff. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A memory corruption vulnerability is present in bspatch as shipped in Colin Percival’s bsdiff tools version 4.3. Insufficient checks when handling external inputs allows an attacker to bypass the sanity checks in place and write out of a dynamically allocated buffer boundaries.

Why this priority

Critical severity
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	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.6% (top 15%)
CISA exploited list	No
Weakness	CWE-787
Published	2020-09-16
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: daemonology

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

Am I affected?

Timeline

2020-09-16 14:15 UTCPublished CVE record published
2026-06-17 02:54 UTCUpdated Record last modified

daemonology bsdiff DOWNGRADE

Affected: 4.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.3

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 4.3 (Debian / Ubuntu)

apt-cache madison bsdiff sudo apt install bsdiff=<VERSION_BEFORE_4.3> sudo apt-mark hold bsdiff

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

dnf --showduplicates list bsdiff sudo dnf downgrade bsdiff-<VERSION_BEFORE_4.3> sudo dnf versionlock add bsdiff

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-2020-14315?

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

Is CVE-2020-14315 being exploited?

CVE-2020-14315 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-2020-14315 affect?

CVE-2020-14315 affects bsdiff. Severity is critical (CVSS 9.8). A memory corruption vulnerability is present in bspatch as shipped in Colin Percival’s bsdiff tools version 4.3. Insufficient checks when handling external inputs allows an attacker to bypass the sanity checks in place and write out of a dy

How urgent is CVE-2020-14315?

Priority 66/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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