How severe is CVE-2026-34838?

CVE-2026-34838 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-34838 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34838?

CVE-2026-34838 affects Intermesh Group-office. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-34838?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-34838 have an EU (EUVD) identifier?

Yes. CVE-2026-34838 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18532.

When was CVE-2026-34838 published?

CVE-2026-34838 was published on 2026-04-02 and last updated on 2026-06-17.

CVE-2026-34838

CVE-2026-34838 is a critical-severity vulnerability in Intermesh Group-office with a CVSS 3.x base score of 9.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.9)
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-18532
Weakness: CWE-502
Affected product: Intermesh Group-office
Published: 2026-04-02
Last modified: 2026-06-17

Description

Group-Office is an enterprise customer relationship management and groupware tool. Prior to versions 6.8.156, 25.0.90, and 26.0.12, a vulnerability in the AbstractSettingsCollection model leads to insecure deserialization when these settings are loaded. By injecting a serialized FileCookieJar object into a setting string, an authenticated attacker can achieve Arbitrary File Write, leading directly to Remote Code Execution (RCE) on the server. This issue has been patched in versions 6.8.156, 25.0.90, and 26.0.12.

Frequently asked questions

What is CVE-2026-34838?: Group-Office is an enterprise customer relationship management and groupware tool. Prior to versions 6.8.156, 25.0.90, and 26.0.12, a vulnerability in the AbstractSettingsCollection model leads to insecure deserialization when these settings are loaded. By injecting a serialized FileCookieJar object into a setting string, an authenticated attacker can achieve Arbitrary File Write, leading directly to Remote Code Execution (RCE) on the server. This issue has been patched in versions 6.8.156, 25.0.90, and 26.0.12.
How severe is CVE-2026-34838?: CVE-2026-34838 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-34838 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34838?: CVE-2026-34838 affects Intermesh Group-office. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34838?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-34838 have an EU (EUVD) identifier?: Yes. CVE-2026-34838 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18532.
When was CVE-2026-34838 published?: CVE-2026-34838 was published on 2026-04-02 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:intermesh:group-office:*:*:*:*:*:*:*:*

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