VulnerabilityPublished 25 May 2026

CVE-2026-48847: Roundcube Webmail · Incorrect Resource Transfer Between Spheres

Affects Roundcube WebmailSource CVE Database V5

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Not known to be exploited · CVSS 3.7 Low : upgrade to 1.7.1 or 1.6.16 when convenient.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score

3.7Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 37% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.7.1, 1.6.16

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Roundcube Webmail to 1.7.1 or 1.6.16.

Affected software

Product	Affected	Fixed in
RoundcubeWebmail	Affected >=1.7.0 <1.7.1	Fixed in 1.7.1
RoundcubeWebmail	Affected >=1.6.0 <1.6.16	Fixed in 1.6.16
GitHubroundcube/roundcubemail`pkg:github/roundcube/roundcubemail`Other threats	Affected =1.6.0 =1.7.0	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, users should consider disabling redis/memcache session storage or restricting access to these services to trusted hosts only to reduce exposure. Monitor for vendor updates regarding patches or official mitigations.

Description

CVE-2026-48847 is a vulnerability in Roundcube Webmail versions 1.6.0 through 1.6.15 and 1.7.0 that allows an unauthenticated attacker to delete arbitrary files by exploiting session poisoning via redis or memcache. The vulnerability is classified under CWE-669, indicating incorrect resource transfer between spheres. The CVSS score is 3.7, reflecting a low severity impact primarily affecting availability with no confidentiality or integrity impact.

Impact

An attacker can delete arbitrary files on the affected system without authentication by exploiting session poisoning in redis or memcache used by Roundcube Webmail. The impact is limited to availability (file deletion) with no direct confidentiality or integrity compromise reported. The low CVSS score reflects the high complexity of attack and limited scope of impact.

Summary

Roundcube Webmail versions prior to 1.6.16 and 1.7.1 contain a vulnerability (CVE-2026-48847) that permits pre-authentication arbitrary file deletion through session poisoning attacks targeting redis or memcache session stores. This vulnerability is categorized as CWE-669, indicating improper handling of resource transfer boundaries. The CVSS 3.1 base score is 3.7, with network attack vector, high attack complexity, no privileges required, no user interaction, and limited impact on availability only.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 1 Jun 2026, 20:59 UTC

WeaknessesCWE-669

Technical details

References

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