CVE-2026-1435: Not properly invalidated session vulnerability in Graylog Web Interface, version 2.2.3, due to incorrect manag

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CRITICAL 9.8REMOTEDOWNGRADE

CVE-2026-1435 is a critical-severity flaw (CVSS 9.8) affecting graylog. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Not properly invalidated session vulnerability in Graylog Web Interface, version 2.2.3, due to incorrect management of session invalidation after new logins. The application generates a new 'sessionId' each time a user authenticates, but does not invalidate previously issued session identifiers, which remain valid even after multiple consecutive logins by the same user. As a result, a stolen or leaked 'sessionId' can continue to be used to authen

Why this priority

Critical severity
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	0.4% (top 64%)
CISA exploited list	No
Weakness	CWE-613
Published	2026-02-18
Last modified	2026-06-17

Publisher (CNA): Spanish National Cybersecurity Institute, S.A. (INCIBE) · Vendor: graylog

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

Am I affected?

Timeline

2026-02-18 14:16 UTCPublished CVE record published
2026-06-17 10:15 UTCUpdated Record last modified

graylog graylog DOWNGRADE

Affected: 2.2.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.2.3

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.2.3 (Debian / Ubuntu)

apt-cache madison graylog sudo apt install graylog=<VERSION_BEFORE_2.2.3> sudo apt-mark hold graylog

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

dnf --showduplicates list graylog sudo dnf downgrade graylog-<VERSION_BEFORE_2.2.3> sudo dnf versionlock add graylog

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-2026-1435?

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

Is CVE-2026-1435 being exploited?

CVE-2026-1435 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-2026-1435 affect?

CVE-2026-1435 affects graylog. Severity is critical (CVSS 9.8). Not properly invalidated session vulnerability in Graylog Web Interface, version 2.2.3, due to incorrect management of session invalidation after new logins. The application generates a new 'sessionId' each time a user authenticates, but do

How urgent is CVE-2026-1435?

Priority 48/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-1441 MEDIUM 6.1 DOWNGRADE Reflected Cross-Site Scripting (XSS) vulnerability in the Graylog Web Interface console, version 2.2.3, caused
CVE-2026-1440 MEDIUM 6.1 DOWNGRADE Reflected Cross-Site Scripting (XSS) vulnerability in the Graylog Web Interface console, version 2.2.3, caused
CVE-2026-1439 MEDIUM 6.1 DOWNGRADE Reflected Cross-Site Scripting (XSS) vulnerability in the Graylog Web Interface console, version 2.2.3, caused
CVE-2026-1438 MEDIUM 6.1 DOWNGRADE Reflected Cross-Site Scripting (XSS) vulnerability in the Graylog Web Interface console, version 2.2.3, caused
CVE-2026-1437 MEDIUM 6.1 DOWNGRADE Reflected Cross-Site Scripting (XSS) vulnerability in the Graylog Web Interface console, version 2.2.3, caused

References

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