What is CVE-2018-20857?

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.

How severe is CVE-2018-20857?

CVE-2018-20857 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2018-20857 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-20857?

CVE-2018-20857 affects Zendesk Samlr. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-20857?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2018-20857 published?

CVE-2018-20857 was published on 2019-07-26 and last updated on 2026-06-17.

CVE-2018-20857

CVE-2018-20857 is a high-severity vulnerability in Zendesk Samlr with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Zendesk Samlr
Published: 2019-07-26
Last modified: 2026-06-17

Description

Zendesk Samlr before 2.6.2 allows an XML nodes comment attack such as a name_id node with [email protected] followed by . and then the attacker's domain name.

Frequently asked questions

What is CVE-2018-20857?: Zendesk Samlr before 2.6.2 allows an XML nodes comment attack such as a name_id node with [email protected] followed by . and then the attacker's domain name.
How severe is CVE-2018-20857?: CVE-2018-20857 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2018-20857 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-20857?: CVE-2018-20857 affects Zendesk Samlr. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-20857?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-20857 published?: CVE-2018-20857 was published on 2019-07-26 and last updated on 2026-06-17.

References

https://github.com/zendesk/samlr/compare/v2.6.1...v2.6.2

Affected products (1)

cpe:2.3:a:zendesk:samlr:*:*:*:*:*:*:*:*

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