CVE-2018-20857 json
samlr XML nodes comment attack
published 7y ago modified 4mo ago also GHSA-qpxp-5j56-gg3x , EUVD-2019-0601
- cvss
- 7.5
- version 3.0, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.2%
- EPSS 1.2% chance of exploitation in 30 days, percentile 68%
- public exploits
- 0
- none known
Summary
Zendesk Samlr before 2.6.2 allows an XML nodes comment attack such as a name_id node with user@example.com followed by <!---->. and then the attacker's domain name.
Patch / fix
- rubygems samlr 2.6.2
- zendesk samlr 2.6.2
- github.com/zendesk/samlr#29 pull request
- github.com/zendesk/samlr/compare/v2.6.1...v2.6.2 advisory
Is CVE-2018-20857 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerExploit prediction
1.21% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.0 | 7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:P/A:N |
| GitHub | 3.0 | 7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| rubygems | samlr | <2.6.2 |
2.6.2 |
Classification
- Weakness
-
- CWE-20 Improper Input Validation
References
-
github.com
/zendesk/samlr/compare/v2.6.1...v2.6.2
web, patch, third-party-advisory
-
github.com
/zendesk/samlr/pull/29
web
-
nvd.nist.gov
/vuln/detail/CVE-2018-20857
advisory
-
github.com
/rubysec/ruby-advisory-db/blob/master/gems/samlr/CVE-2018-20857.yml
web
-
github.com
/zendesk/samlr
package
Sources
- CVE List CVE-2018-20857
- GitHub Advisory GHSA-qpxp-5j56-gg3x
- NVD CVE-2018-20857
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.