CVE-2021-3311

mediumpriority · track · 40EPSS 0.029 · 87 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

2.90% (87th) EPSS

CVSS 6.8 · medium

Is it mine?

4 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-27

An issue was discovered in October through build 471. It reactivates an old session ID (which had been invalid after a logout) once a new login occurs. NOTE: this violates the intended Auth/Manager.php authentication behavior but, admittedly, is only relevant if an old session ID is known to an attacker.

cvss

Technical severity, 0–10. One row per scoring source.

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 6.8–9.8

v2.06.8mediumAV:N/AC:M/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8.6 · impact 6.4

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 5.9

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · OSV

v3.19criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-613USprimaryCWE-613US

affected products (4)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
octobercms october≤ 1.0.471nvdUScpe:2.3:a:octobercms:october:*:*:*:*:*:*:*:*
Packagist october/rain< 1.0.472osvUSpkg:composer/october/rain
Packagist october/rain1.1.0 → 1.1.2osvUSpkg:composer/october/rain

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-7ggw-h8pp-r95rOctober CMS Session ID not invalidated after logout2021-02-10ghsa · osvUS
### Impact When logging out, the session ID was not invalidated. This is not a problem while the user is logged out, but as soon as the user logs back in the old session ID would be valid again; which means that anyone that gained access to the old session cookie would be able to act as the logged in user. This is not a major concern for the majority of cases, since it requires a malicious party gaining access to the session cookie in the first place, but nevertheless has been fixed. ### Patches Issue has been patched in Build 472 (v1.0.472) and v1.1.2. ### Workarounds Apply https://github.com/octobercms/library/commit/642f597489e6f644d4bd9a0c267e864cabead024 to your installation manually if unable to upgrade to Build 472 or v1.1.2. ### References - Reported by Anisio (Brazilian Information Security Analyst) - http://cve.circl.lu/cve/CVE-2021-3311 ### For more information If you have any questions or comments about this advisory: * Email us at [hello@octobercms.com](mailto:hello@octobercms.com) ### Threat assessment: <img width="699" alt="Screen Shot 2021-02-07 at 11 50 35 PM" src="https://user-images.githubusercontent.com/7253840/107180881-51eaf000-699f-11eb-8828-333128faf2a6.png">

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2021-02-05modified 2026-06-17

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+728 more

references (10)

External citations — patches, advisories, analysis.

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