CVE-2026-62641Network attack vector

Denial of service via unbounded compressed-RTF decoding

Published Jul 14, 2026 · Updated Jul 14, 2026

Denial of service in Roundcube Webmail before 1.6.17 and 1.7.0 through 1.7.1 allows remote attackers to interrupt TNEF decoding. The _decompressRTF method trusts the declared output size and continues its decode loop after the compressed input buffer is exhausted. A recipient must interact with a crafted winmail.dat attachment, and the demonstrated consequence is limited to availability loss during message processing.

CVSS severity4.3
Medium
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Roundcube Webmail before 1.6.17 and 1.7.0 through 1.7.1 allows remote attackers to interrupt TNEF decoding. The _decompressRTF method trusts the declared output size and continues its decode loop after the compressed input buffer is exhausted. A recipient must interact with a crafted winmail.dat attachment, and the demonstrated consequence is limited to availability loss during message processing.

The record

CVE
CVE-2026-62641
Published
Jul 14, 2026
Updated
Jul 14, 2026
Vendor
Roundcube
Product
Roundcube Webmail
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.6.0 <1.6.17
  2. Affected versionversion=1.7.0 <1.7.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Roundcube · Roundcube Webmailversion=1.6.0 <1.6.17; version=1.7.0 <1.7.2

Published CVSS scores

4.3MITRECVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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