CVE-2020-5205
Session fixation attack in Pow (Hex package)
In Pow (Hex package) before 1.0.16, the use of Plug.Session in Pow.Plug.Session is susceptible to session fixation attacks if a persistent session store is used for Plug.Session, such as Redis or a database. Cookie store, which is used in most Phoenix apps, doesn't have this vulnerability.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Session fixation attack in Pow (Hex package)
In Pow (Hex package) before 1.0.16, the use of Plug.Session in Pow.Plug.Session is susceptible to session fixation attacks if a persistent session store is used for Plug.Session, such as Redis or a database. Cookie store, which is used in most Phoenix apps, doesn't have this vulnerability.
- Record
CVE-2020-5205- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N - Weakness
- CWE-384
- Updated
- 2026-11-02
EUVDEUVD-2022-1831
In Pow (Hex package) before 1.0.16, the use of Plug.Session in Pow.Plug.Session is susceptible to session fixation attacks if a persistent session store is used for Plug.Session, such as Redis or a database. Cookie store, which is used in most Phoenix apps, doesn't have this vulnerability.
- Record
EUVD-2022-1831- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-v2wf-c3j6-wpvw
Session fixation
Impact
The use of Plug.Session in Pow.Plug.Session is susceptible to session fixation attacks if a persistent session store is used for Plug.Session, such as Redis or a database. Cookie store, which is used in most Phoenix apps, doesn't have this vulnerability.
Workarounds
Call Plug.Conn.configure_session(conn, renew: true) periodically and after privilege change. A custom authorization plug can be written where the create/3 method should return the conn only after Plug.Conn.configure_session/2 have been called on it.
References
https://github.com/danschultzer/pow/commit/578ffd3d8bb8e8a26077b644222186b108da474f
https://www.owasp.org/index.php/Session_fixation
- Record
GHSA-v2wf-c3j6-wpvw- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N - Weakness
- CWE-384
- Updated
- 2026-11-02
NVD
In Pow (Hex package) before 1.0.16, the use of Plug.Session in Pow.Plug.Session is susceptible to session fixation attacks if a persistent session store is used for Plug.Session, such as Redis or a database. Cookie store, which is used in most Phoenix apps, doesn't have this vulnerability.
- Record
CVE-2020-5205- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N - CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - CVSS 2.0
- 5.5 Medium
AV:N/AC:L/Au:S/C:P/I:P/A:N - Weakness
- CWE-384
- Updated
- 2026-11-02
OSV
In Pow (Hex package) before 1.0.16, the use of Plug.Session in Pow.Plug.Session is susceptible to session fixation attacks if a persistent session store is used for Plug.Session, such as Redis or a database. Cookie store, which is used in most Phoenix apps, doesn't have this vulnerability.
- Record
CVE-2020-5205- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-v2wf-c3j6-wpvw
Session fixation
Impact
The use of Plug.Session in Pow.Plug.Session is susceptible to session fixation attacks if a persistent session store is used for Plug.Session, such as Redis or a database. Cookie store, which is used in most Phoenix apps, doesn't have this vulnerability.
Workarounds
Call Plug.Conn.configure_session(conn, renew: true) periodically and after privilege change. A custom authorization plug can be written where the create/3 method should return the conn only after Plug.Conn.configure_session/2 have been called on it.
References
https://github.com/danschultzer/pow/commit/578ffd3d8bb8e8a26077b644222186b108da474f
https://www.owasp.org/index.php/Session_fixation
- Record
GHSA-v2wf-c3j6-wpvw- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N - Weakness
- CWE-384
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
powHex |
before 1.0.16 | 1.0.16 |
powHex |
before 1.0.16, plus listed versions 0.1.0-alpha0.1.0-alpha.10.1.0-alpha.20.1.0-alpha.30.1.0-alpha.4 Show 26 moreShow less0.1.0-alpha.50.1.0-alpha.60.1.0-alpha.70.1.0-alpha.80.1.0-rc.11.0.01.0.0-rc.01.0.0-rc.11.0.0-rc.21.0.0-rc.31.0.0-rc.41.0.11.0.101.0.111.0.121.0.131.0.141.0.151.0.21.0.31.0.41.0.51.0.61.0.71.0.81.0.9 |
1.0.16 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, products | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-5205 is a medium vulnerability (CVSS 6.5) in Danschultzer Pow, published January 9, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.77%, the 55th percentile. Fixed in pow 1.0.16.
References
github.com/danschultzer/pow/security/advisories/GHSA-v2wf-c3j6-wpvw
nvd.nist.gov/vuln/detail/CVE-2020-5205