CVE-2021-37621 | Denial of service due to infinite loop in Image::printIFDStructure

Exiv2 is a command-line utility and C++ library for reading, writing, deleting, and modifying the metadata of image files. An infinite loop was found in Exiv2 versions v0.27.4 and earlier. The infinite loop is triggered when Exiv2 is used to print the metadata of a crafted image file. An attacker could potentially exploit the vulnerability to cause a denial of service, if they can trick the victim into running Exiv2 on a crafted image file. Note that this bug is only triggered when printing the image ICC profile, which is a less frequently used Exiv2 operation that requires an extra command line option (`-p C`). The bug is fixed in version v0.27.5.

Published: 2021-08-09 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-37621 is rated Moderate Risk (44.5/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.10%). EPSS rose +1.02% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

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

Exploit prediction scoring system (EPSS) score for CVE-2021-37621

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 0.09% 1.10% +1.02%
2 2025-11-21 0.23% 0.09% -0.14%
3 2025-11-18 — 0.23% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-37621

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2021-37621

OS Trackers for CVE-2021-37621

vendor priority summary link
alpine — CVE-2021-37621: 1 source package rows (exiv2); 20 state rows across 8 repos (3.11-main, 3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 13. https://security.alpinelinux.org/vuln/CVE-2021-37621
debian not yet assigned CVE-2021-37621 not yet assigned priority: Debian including 1 source packages (exiv2), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-37621
gentoo high CVE-2021-37621: 1 GLSA(s) (202312-06), 1 atom(s) (media-gfx/exiv2); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-37621
redhat low — https://access.redhat.com/security/cve/CVE-2021-37621
suse medium CVE-2021-37621 severity moderate: SUSE including 25 source package names (exiv2, exiv2-0.26-150000.6.16.1, …), 140 product×package rows across 57 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (57 product lines)): Fixed 100, Known Not Affected 40. https://www.suse.com/security/cve/CVE-2021-37621/
ubuntu medium CVE-2021-37621 medium priority: Ubuntu including 1 source packages (exiv2), 8 status rows across 8 suites (bionic, focal, hirsute, impish, jammy, trusty, upstream, xenial): released 4, not-affected 2, DNE 1, needs-triage 1. https://ubuntu.com/security/CVE-2021-37621

Affected software / configurations for CVE-2021-37621

Vendor Product Version Raw CPE
exiv2 exiv2 <= 0.27.4 cpe:2.3:a:exiv2:exiv2:*:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

References for CVE-2021-37621

cvelogic Threat Intelligence