NVD / CVE Program· CNA redhat

CVE-2021-3521: There is a flaw in RPM's signature functionality.

MediumCVSS 4.7 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 18/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.32% (FIRST EPSS).
Someone with local access to the system can trigger it. No account or password is required. A user must open a link or visit a page. Special conditions such as timing or configuration are required.
Fixed version: rpm-build (AlmaLinux:8) 4.14.3-19.el8_5.2; rpm-plugin-fapolicyd (AlmaLinux:8) 4.14.3-19.el8_5.2; rpm (Alpine:v3.17) 4.17.1-r0.
Mentioned 5 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to rpm-build (AlmaLinux:8) 4.14.3-19.el8_5.2; rpm-plugin-fapolicyd (AlmaLinux:8) 4.14.3-19.el8_5.2; rpm (Alpine:v3.17) 4.17.1-r0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

There is a flaw in RPM's signature functionality. OpenPGP subkeys are associated with a primary key via a "binding signature." RPM does not check the binding signature of subkeys prior to importing them. If an attacker is able to add or socially engineer another party to add a malicious subkey to a legitimate public key, RPM could wrongly trust a malicious signature. The greatest impact of this flaw is to data integrity. To exploit this flaw, an attacker must either compromise an RPM repository or convince an administrator to install an untrusted RPM or public key. It is strongly recommended to only use RPMs and public keys from trusted sources.

Weak crypto

Published: Aug 22, 2022
Updated: Jun 17, 2026
EPSS: 0.3% · 25th percentile
CWE: CWE-347

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 18 / 40 · 4.7 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.3%

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
rpm	rpm	cpe:2.3:a:rpm:rpm

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

n/a RPM
- Fixed in rpm-4.18.0-beta1, rpm-4.18.0-alpha2, rpm-4.18.0-alpha1 .affected

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

rpm rpmbefore 4.17.1

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
AlmaLinux:8	rpm-build	before 4.14.3-19.el8_5.2	4.14.3-19.el8_5.2
AlmaLinux:8	rpm-plugin-fapolicyd	before 4.14.3-19.el8_5.2	4.14.3-19.el8_5.2
Alpine:v3.17	rpm	before 4.17.1-r0	4.17.1-r0
Debian:12	rpm	before 4.18.0+dfsg-1	4.18.0+dfsg-1
openSUSE:Leap Micro 5.4	python-rpm	before 4.14.3-150400.59.16.1	4.14.3-150400.59.16.1
openSUSE:Leap Micro 5.4	rpm	before 4.14.3-150400.59.16.1	4.14.3-150400.59.16.1
openSUSE:Leap Micro 5.4	rpm-ndb	before 4.14.3-150400.59.16.1	4.14.3-150400.59.16.1
openSUSE:Tumbleweed	rpm	before 4.17.1-1.1	4.17.1-1.1
Red Hat:enterprise_linux:8::appstream	python3-rpm-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-build	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-build-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-build-libs-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-debugsource	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-devel-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-libs-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-plugin-fapolicyd	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-plugin-fapolicyd-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-plugin-ima-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-plugin-prioreset-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-plugin-selinux-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-plugin-syslog-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-plugin-systemd-inhibit-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2
Red Hat:enterprise_linux:8::appstream	rpm-sign-debuginfo	before 0:4.14.3-19.el8_5.2	0:4.14.3-19.el8_5.2

+73

Same product

rpm: all records

Other highest-scoring records for the same primary product.

CVE-2014-8118Integer overflow in RPM 4.12 and earlier allows remote attackers to execute arbitrary code via a crafted CPIO header in the payload section…
42Plan
CVE-2011-3378RPM 4.4.x through 4.9.x, probably before 4.9.1.2, allows remote attackers to cause a denial of service (memory corruption) and possibly…
39Monitor
CVE-2013-6435Race condition in RPM 4.11.1 and earlier allows remote attackers to execute arbitrary code via a crafted RPM file whose installation…
32Monitor

Published before and after this one in the same product

← EarlierCVE-2021-20266Apr 30, 2021 · A flaw was found in RPM's hdrblobInit() in lib/header.c.
19Monitor
← EarlierCVE-2021-3421May 19, 2021 · A flaw was found in the RPM package in the read functionality.
22Monitor
Later →CVE-2021-35937Aug 25, 2022 · A race condition vulnerability was found in rpm.
25Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
almalinux:rpm-build	4.14.3-19.el8_5.2 · AlmaLinux:8	Package registry (OSV)
almalinux:rpm-plugin-fapolicyd	4.14.3-19.el8_5.2 · AlmaLinux:8	Package registry (OSV)
alpine:rpm	4.17.1-r0 · Alpine:v3.17	Package registry (OSV)
debian:rpm	4.18.0+dfsg-1 · Debian:12	Package registry (OSV)
opensuse:python-rpm	4.14.3-150400.59.16.1 · openSUSE:Leap Micro 5.4	Package registry (OSV)
opensuse:rpm	4.14.3-150400.59.16.1 · openSUSE:Leap Micro 5.4	Package registry (OSV)
opensuse:rpm-ndb	4.14.3-150400.59.16.1 · openSUSE:Leap Micro 5.4	Package registry (OSV)
red hat:python3-rpm-debuginfo	0:4.14.3-14.el8_4.2 · Red Hat:rhel_eus:8.4::appstream	Package registry (OSV)
red hat:rpm-build	0:4.14.3-14.el8_4.2 · Red Hat:rhel_eus:8.4::appstream	Package registry (OSV)
red hat:rpm-build-debuginfo	0:4.14.3-14.el8_4.2 · Red Hat:rhel_eus:8.4::appstream	Package registry (OSV)
red hat:rpm-build-libs-debuginfo	0:4.14.3-14.el8_4.2 · Red Hat:rhel_eus:8.4::appstream	Package registry (OSV)
red hat:rpm-debuginfo	0:4.14.3-14.el8_4.2 · Red Hat:rhel_eus:8.4::appstream	Package registry (OSV)
red hat:rpm-debugsource	0:4.14.3-14.el8_4.2 · Red Hat:rhel_eus:8.4::appstream	Package registry (OSV)
red hat:rpm-devel-debuginfo	0:4.14.3-14.el8_4.2 · Red Hat:rhel_eus:8.4::appstream	Package registry (OSV)
red hat:rpm-libs-debuginfo	0:4.14.3-14.el8_4.2 · Red Hat:rhel_eus:8.4::appstream	Package registry (OSV)
red hat:rpm-plugin-fapolicyd	0:4.14.3-14.el8_4.2 · Red Hat:rhel_eus:8.4::appstream	Package registry (OSV)
red hat:rpm-plugin-fapolicyd-debuginfo	0:4.14.3-14.el8_4.2 · Red Hat:rhel_eus:8.4::appstream	Package registry (OSV)
red hat:rpm-plugin-ima-debuginfo	0:4.14.3-14.el8_4.2 · Red Hat:rhel_eus:8.4::appstream	Package registry (OSV)
red hat:rpm-plugin-prioreset-debuginfo	0:4.14.3-14.el8_4.2 · Red Hat:rhel_eus:8.4::appstream	Package registry (OSV)
rocky linux:rpm	0:4.14.3-19.el8_5.2 · Rocky Linux:8	Package registry (OSV)
suse:python-rpm	4.14.3-150400.59.16.1 · SUSE:Linux Enterprise Micro 5.4	Package registry (OSV)
suse:rpm	4.14.3-150400.59.16.1 · SUSE:Linux Enterprise Micro 5.4	Package registry (OSV)
suse:rpm-ndb	4.14.3-150400.59.16.1 · SUSE:Linux Enterprise Micro 5.4	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-22-0552 · Aug 15, 2022(RedHat Güvenlik Güncellemesi)
TR-22-0222 · Mar 15, 2022(RedHat Güvenlik Güncellemesi)
TR-22-0167 · Feb 23, 2022(RedHat Güvenlik Güncellemesi)
TR-22-0127 · Feb 10, 2022(RedHat Güvenlik Zafiyeti)
TR-22-0086 · Jan 26, 2022(RedHat Güvenlik Güncellemesi)

All national notices →

Not on record for this CVE: EPSS history · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

Someone with local access to the system can trigger it.
No account or password is required.
A user must open a link or visit a page.
Special conditions such as timing or configuration are required.

If successful

Confidentiality: none
Integrity: high · data or configuration can be modified
Availability: none

Attack vector: Local
Attack complexity: High
Privileges required: None
User interaction: Required
Scope: Unchanged
Confidentiality impact: None
Integrity impact: High
Availability impact: None

Weakness class (CWE)

CWE-347 · Improper Verification of Cryptographic Signature

CVSS vector

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

nvd-primary

Root cause

The verifier takes the algorithm to verify with from the token’s own header. Untrusted data ends up deciding its own verification rule.

The bug in code

The whole CWE-347 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const claims = jwt.verify(token, publicKey);

Fixed

1const claims = jwt.verify(token, publicKey, {
2  algorithms: ["RS256"],
3  issuer: "https://id.example.com",
4  audience: "portal",
5});

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log (1)

Fix✗ → ✓Sep 28, 2026, 10:47 PM UTC

For records you follow, these changes also arrive as notifications. →

References

access.redhat.com/security/cve/CVE-2021-3521

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records