What is CVE-2021-21311?

CVE-2021-21311 is SSRF in adminer. The supplied enrichment data classifies it as SSRF mapped to CWE-918 Server-Side Request Forgery (SSRF).

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Yes: CISA KEV signal present. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

Is there a public exploit?

38 public PoC repositories reported; 1 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS, cloud metadata access logs, egress proxy logs where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2021-21311 using CVSS 7.2, EPSS 98%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

Publicly linked actor or ransomware signals in the supplied enrichment data: The White Company (), APT 22 (), Operation Red Signature (), Red October (), Infy (). Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Treat as emergency remediation because CISA KEV status is present. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

CISA KEVhighSSRFpublic exploit

CVE-2021-21311

CVE-2021-21311 — SSRF in adminer

Q: Is it in CISA KEV?

Yes. The supplied enrichment data lists CVE-2021-21311 in CISA KEV with required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Adminer is an open-source database management in a single PHP file. In adminer from version 4.0.0 and before 4.7.9 there is a server-side request forgery vulnerability. Users of Adminer versions bundling all drivers (e.g. `adminer.php`) are affected. This is fixed in version 4.7.9.

Published Feb 11, 2021Updated Jun 17, 2026Sources: NVD, vrana (CNA), CISA, FIRST EPSS, GitHub, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Confirmed

CISA KEV, listed Sep 29, 2025

EPSS

98%

top of FIRST's scoreset

Affects

vrana

adminer

CVSS base

7.2

high · 2 sources

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

Active

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade adminer to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

CISA required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Federal deadline Oct 20, 2025 — passed 349 days ago

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Treat as emergency remediation because CISA KEV status is present.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
vrana	adminer	>= 4.0.0, < 4.7.9	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

None

Confidentiality

Low

Integrity

Low

Scope

Changed

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
7.2	CVSS 3.1	high	3.9	2.7	GitHub (CNA), NVD, vrana (CNA)
6.4	CVSS 2.0	medium	10	4.9	NVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-918 · Server-Side Request Forgery (SSRF)

Read Application Data
Execute Unauthorized Code or Commands::

Weakness & attack patterns

CWE-918Server-Side Request Forgery (SSRF)

Inferred from the weakness class — not observed against this CVE.

CAPEC-664 · Server Side Request Forgery

CISA KEV details

CISA lists a CVE here once it has evidence of exploitation against real targets.

CISAThat month →

Listed

Sep 29, 2025

Federal deadline

Oct 20, 2025

passed 349 days ago

Ransomware use

Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

1 of the 5 sampled are weaponized

Exploit entries

Exploit-DB and CTI exploit indexes

Social mentions

Posts naming this CVE. Attention, not evidence of exploitation — it spikes on disclosure and decays whether or not anything is exploited.

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Prioritize edge telemetry for network-reachable adminer.
Monitor for scanner or exploit-pattern traffic after 38 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPScloud metadata access logsegress proxy logs

Exposure queries

Search-engine queries that surface exposed instances. Run them against your own estate first.

title:"Login - Adminer"

Groups associated with this CVE

Groups reported in connection with this vulnerability. A reported association, not a confirmed observation of that group using it — and not scoped to any sector or campaign.

The White CompanyAPT 22Operation Red SignatureRed OctoberInfy

ip62.28.83.8370
AbuseIPDB Hourly Update · May 20, 2025

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 7.2 (AV:N)
Jun 17, 2026 · NVD
2025
Bulletin released on NIST.
Oct 1, 2025 · SOCRadar CTI
Cve is exploited Adminer Server-Side Request Forgery Vulnerability
Sep 30, 2025 · SOCRadar CTI
Bulletin released on NIST.
Sep 30, 2025 · SOCRadar CTI
Added to CISA KEV catalog
Sep 29, 2025 · CISA
2024
CVE is exploited. "k0mi-tg/CVE-POC"
Feb 1, 2024 · SOCRadar CTI
2023
CVE is exploited. "HimmelAward/Goby_POC"
Dec 5, 2023 · SOCRadar CTI
CVE is exploited. "KayCHENvip/vulnerability-poc"
Dec 5, 2023 · SOCRadar CTI
CVE is exploited. "Threekiii/Awesome-POC"
Dec 5, 2023 · SOCRadar CTI
CVE is exploited. "WhooAmii/POC_to_review"
Dec 5, 2023 · SOCRadar CTI
CVE is exploited. "manas3c/CVE-POC"
Dec 5, 2023 · SOCRadar CTI
CVE is exploited. "nomi-sec/PoC-in-GitHub"
Dec 5, 2023 · SOCRadar CTI
CVE is exploited. "soosmile/POC"
Dec 5, 2023 · SOCRadar CTI
2021
Initial · CVE published
Feb 11, 2021 · NVD

Source activity

Readings a source repeats on a schedule, counted rather than listed.

8×ModifiedSep 27, 2025 – Oct 24, 2025 · SOCRadar CTI
5×Github ReposDec 5, 2023 – Feb 2, 2024 · SOCRadar CTI
4×TweetsJun 20, 2024 – Mar 24, 2026 · SOCRadar CTI
1×1 time mentioned on 1 Telegram channelJun 2, 2025 · SOCRadar CTI

References

7 on the record

github.com/vrana/adminer/commit/ccd2374b0b12bd547417bf0dacdf153826c83351
Patch, NIST, MITRE_REFERENCES
github.com/vrana/adminer/files/5957311/Adminer.SSRF.pdf
Exploit, Third Party Advisory, NIST, MITRE_REFERENCES
github.com/vrana/adminer/security/advisories/GHSA-x5r2-hj5c-8jx6
Patch, Third Party Advisory, NIST, MITRE_REFERENCES, Vendor Advisory
lists.debian.org/debian-lts-announce/2021/03/msg00002.html
Mailing List, Third Party Advisory, NIST, Mitre
packagist.org/packages/vrana/adminer
Product, Third Party Advisory, NIST, MITRE_REFERENCES
www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21311
US Government Resource
nvd.nist.gov/vuln/detail/CVE-2021-21311
Vendor Advisory

Coverage

6 stories from the feeds we poll

1 more reports on this CVEShowing 5 of 6 · Vendor research and security press coverageUnlock free

Elsewhere on this site

vranaevery CVE for this vendor
September 2025what else CISA listed
SSRFsame class
CWE-918other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

Only the 1 indicator(s) reported for this CVE are available; no packet-level or host-forensic artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2021-21311 is SSRF in adminer, a high vulnerability affecting adminer from vrana. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 38 public PoC repositories reported; 1 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 7.2 describes technical severity, while EPSS 98% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.