CVE-2026-34392: LORIS (Longitudinal Online Research and Imaging System) is a self-hosted web application that provides data- a

Routine

HIGH 7.5REMOTEUPGRADE

CVE-2026-34392 is a high-severity flaw (CVSS 7.5) affecting loris. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

LORIS (Longitudinal Online Research and Imaging System) is a self-hosted web application that provides data- and project-management for neuroimaging research. From 20.0.0 to before 27.0.3 and 28.0.1, a bug in the static file router can allow an attacker to traverse outside of the intended directory, allowing unintended files to be downloaded through the static, css, and js endpoints. This vulnerability is fixed in 27.0.3 and 28.0.1.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 84%)
CISA exploited list	No
Weakness	CWE-552
Published	2026-04-08
Last modified	2026-07-24

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

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-08 19:25 UTCPublished CVE record published
2026-07-24 22:10 UTCUpdated Record last modified

mcgill loris UPGRADE

Affected: >= 20.0.0 and < 27.0.3 · 28.0.0

Fixed in: 27.0.3

Safe to downgrade to: a release before 20.0.0

1. Check installed version

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

2. UPGRADE to 27.0.3 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade loris

Note

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

3. If no update is available yet, DOWNGRADE to a release before 20.0.0 (Debian / Ubuntu)

apt-cache madison loris sudo apt install loris=<VERSION_BEFORE_20.0.0> sudo apt-mark hold loris

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list loris sudo dnf downgrade loris-<VERSION_BEFORE_20.0.0> sudo dnf versionlock add loris

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-2026-34392?

loris: upgrade to 27.0.3. Exact commands for each OS are on this page.

Is CVE-2026-34392 being exploited?

CVE-2026-34392 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-2026-34392 affect?

CVE-2026-34392 affects loris. Severity is high (CVSS 7.5). LORIS (Longitudinal Online Research and Imaging System) is a self-hosted web application that provides data- and project-management for neuroimaging research. From 20.0.0 to before 27.0.3 and 28.0.1, a bug in the static file router can allo

How urgent is CVE-2026-34392?

Priority 35/100. High severity; Remotely exploitable, no login, no user action

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References

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