CVE-2019-20849

Post-logout cookie disclosure via incomplete cleanup

Published Jun 19, 2020 · Updated Aug 5, 2024

Incomplete cleanup in Mattermost Mobile Apps before 1.26.0 allows attackers with device access to recover cookie data after logout. The logout path fails to remove cookie data stored on the device; public advisories do not identify the affected routine or storage layer. Exploitation requires access to residual application data after an authenticated user logs out, and the documented impact is limited to cookie disclosure.

CVSS severity5.3
Medium
EPSS probability0.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incomplete cleanup in Mattermost Mobile Apps before 1.26.0 allows attackers with device access to recover cookie data after logout. The logout path fails to remove cookie data stored on the device; public advisories do not identify the affected routine or storage layer. Exploitation requires access to residual application data after an authenticated user logs out, and the documented impact is limited to cookie disclosure.

The record

CVE
CVE-2019-20849
Published
Jun 19, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-459, T1539
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Jun 19, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
5.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-459Incomplete Cleanup
T1539Steal Web Session Cookie

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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