CVE-2021-25742 | Ingress-nginx custom snippets allows retrieval of ingress-nginx serviceaccount token and secrets across all namespaces

Exp

A security issue was discovered in ingress-nginx where a user that can create or update ingress objects can use the custom snippets feature to obtain all secrets in the cluster.

Published: 2021-10-29 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-25742 is rated High Exploit Risk (72.9/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.78%). 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +1.17% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-25742

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-25742

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.61% 1.78% +1.17%
2 2026-03-04 0.55% 0.61% +0.06%
3 2026-03-03 — 0.55% —

Full EPSS history (29 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-25742

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.6 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.8 4.7 [email protected]
7.1 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 4.2 [email protected]
5.5 2.0 MEDIUM
AV:N/AC:L/Au:S/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.0 4.9 [email protected]

Weakness enumeration for CVE-2021-25742

OS Trackers for CVE-2021-25742

vendor priority summary link
redhat high — https://access.redhat.com/security/cve/CVE-2021-25742

Affected software / configurations for CVE-2021-25742

Vendor Product Version Raw CPE
kubernetes ingress-nginx < 0.49.1 cpe:2.3:a:kubernetes:ingress-nginx:*:*:*:*:*:*:*:*
kubernetes ingress-nginx 1.0.0 cpe:2.3:a:kubernetes:ingress-nginx:1.0.0:*:*:*:*:*:*:*
netapp trident — cpe:2.3:a:netapp:trident:-:*:*:*:*:*:*:*

References for CVE-2021-25742

URL Tags
https://github.com/kubernetes/ingress-nginx/issues/7837 Exploit Issue Tracking Mitigation Third Party Advisory
https://groups.google.com/g/kubernetes-security-announce/c/mT4JJxi9tQY Mailing List Mitigation Third Party Advisory
https://security.netapp.com/advisory/ntap-20211203-0001/ Third Party Advisory
cvelogic Threat Intelligence