CVE-2026-33645: Fireshare facilitates self-hosted media and link sharing

Routine

HIGH 7.1DOWNGRADE

CVE-2026-33645 is a high-severity flaw (CVSS 7.1) affecting fireshare. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Fireshare facilitates self-hosted media and link sharing. In version 1.5.1, an authenticated path traversal vulnerability in Fireshare’s chunked upload endpoint allows an attacker to write arbitrary files outside the intended upload directory. The `checkSum` multipart field is used directly in filesystem path construction without sanitization or containment checks. This enables unauthorized file writes to attacker-chosen paths writable by the Fir

Why this priority

High severity

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

Risk facts

CVSS score	7.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 62%)
CISA exploited list	No
Weakness	CWE-22, CWE-73
Published	2026-03-26
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: shaneisrael

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

Am I affected?

Timeline

2026-03-26 21:17 UTCPublished CVE record published
2026-06-17 10:37 UTCUpdated Record last modified

shaneisrael fireshare DOWNGRADE

Affected: 1.5.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.5.1

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.5.1 (Debian / Ubuntu)

apt-cache madison fireshare sudo apt install fireshare=<VERSION_BEFORE_1.5.1> sudo apt-mark hold fireshare

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

dnf --showduplicates list fireshare sudo dnf downgrade fireshare-<VERSION_BEFORE_1.5.1> sudo dnf versionlock add fireshare

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-2026-33645?

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

Is CVE-2026-33645 being exploited?

CVE-2026-33645 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-2026-33645 affect?

CVE-2026-33645 affects fireshare. Severity is high (CVSS 7.1). Fireshare facilitates self-hosted media and link sharing. In version 1.5.1, an authenticated path traversal vulnerability in Fireshare’s chunked upload endpoint allows an attacker to write arbitrary files outside the intended upload directo

How urgent is CVE-2026-33645?

Priority 34/100. High severity

Related CVEs

CVE-2026-34745 CRITICAL 9.1 UPGRADE Fireshare facilitates self-hosted media and link sharing

References

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