CVE-2021-26917: PyBitmessage through 0.6.3.2 allows attackers to write screen captures to Potentially Unwanted Directories via

Q: How do I fix CVE-2021-26917?

pybitmessage: upgrade to newer than 0.6.3.2. Exact commands for each OS are on this page.

Q: Is CVE-2021-26917 being exploited?

CVE-2021-26917 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-26917 affect?

CVE-2021-26917 affects pybitmessage. Severity is medium (CVSS 5.5). PyBitmessage through 0.6.3.2 allows attackers to write screen captures to Potentially Unwanted Directories via a crafted apinotifypath value. NOTE: the discoverer states "security mitigation may not be necessary as there is no evidence yet

Q: How urgent is CVE-2021-26917?

Priority 36/100. Public exploit reference

Routine

MEDIUM 5.5UPGRADE

CVE-2021-26917 is a medium-severity flaw (CVSS 5.5) affecting pybitmessage. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

PyBitmessage through 0.6.3.2 allows attackers to write screen captures to Potentially Unwanted Directories via a crafted apinotifypath value. NOTE: the discoverer states "security mitigation may not be necessary as there is no evidence yet that these screen intercepts are actually transported away from the local host." NOTE: it is unclear whether there are any common use cases in which apinotifypath is controlled by an attacker

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 54%)
CISA exploited list	No
Published	2021-02-08
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: bitmessage

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

Am I affected?

Timeline

2021-02-08 23:15 UTCPublished CVE record published
2026-06-17 03:44 UTCUpdated Record last modified

bitmessage pybitmessage UPGRADE

Affected: <= 0.6.3.2

Fixed in: newer than 0.6.3.2

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 0.6.3.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade pybitmessage

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade pybitmessage

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2021-26917?

pybitmessage: upgrade to newer than 0.6.3.2. Exact commands for each OS are on this page.

Is CVE-2021-26917 being exploited?

CVE-2021-26917 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-2021-26917 affect?

CVE-2021-26917 affects pybitmessage. Severity is medium (CVSS 5.5). PyBitmessage through 0.6.3.2 allows attackers to write screen captures to Potentially Unwanted Directories via a crafted apinotifypath value. NOTE: the discoverer states "security mitigation may not be necessary as there is no evidence yet

How urgent is CVE-2021-26917?

Priority 36/100. Public exploit reference

Related CVEs

CVE-2018-1000070 HIGH 8.8 DOWNGRADE Bitmessage PyBitmessage version v0.6.2 (and introduced in or after commit 8ce72d8d2d25973b7064b1cf76a6b0b3d62f

References

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