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CVE Record

CVE-2021-29623: Uninitialized variable bug in Exiv2

Exiv2 is a C++ library and a command-line utility to read, write, delete and modify Exif, IPTC, XMP and ICC image metadata. A read of uninitialized memory was found in Exiv2 versions v0.27.3 and earlier. Exiv2 is a command-line utility and C++ library for reading, writing, deleting, and modifying the metadata of image files. The read of uninitialized memory is triggered when Exiv2 is used to read the metadata of a crafted image file. An attacker could potentially exploit the vulnerability to leak a few bytes of stack memory, if they can trick the victim into running Exiv2 on a crafted image file. The bug is fixed in version v0.27.4.

LowCVSS 3.6Not KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This is a low-severity Exiv2 flaw where opening a malicious image for metadata parsing can expose a small amount of stack memory. It requires the victim system or user to process the crafted file. The bug is fixed in Exiv2 v0.27.4.

Executive priority

Treat as routine patching unless Exiv2 processes untrusted images in business workflows. The likely impact is limited memory disclosure, not remote system takeover, but internet-facing image processing increases relevance.

Technical view

Exiv2 v0.27.3 and earlier can read uninitialized memory while parsing metadata from a crafted image. The CVSS vector requires local interaction and user involvement, with low confidentiality and integrity impact and no availability impact. The issue maps to CWE-908.

Likely exposure

Exposure is most likely where Exiv2 CLI or the Exiv2 library processes untrusted images, such as metadata inspection workflows, upload handling, or analyst workstations. Confirm actual exposure through local package and dependency inventory.

Exploitation context

The sources describe potential leakage of a few bytes of stack memory if a victim runs Exiv2 on a crafted image. CISA KEV status is false in the bundle, and no cited source states active exploitation.

Researcher notes

The public record identifies the affected range as versions before v0.27.4 and the trigger as crafted image metadata parsing. Evidence provided does not include active exploitation, broad impact details, or a named workaround beyond upgrading.

Mitigation direction

  • Upgrade Exiv2 to v0.27.4 or later.
  • Apply fixed distribution packages from your operating-system vendor.
  • Avoid processing untrusted images with vulnerable Exiv2 builds.
  • Check vendor advisories before relying on alternate mitigations.

Validation and detection

  • Inventory installed Exiv2 versions and linked library dependencies.
  • Find services or scripts that invoke Exiv2 on uploaded images.
  • Confirm patched packages are deployed on image-processing hosts.
  • Review vendor advisories for your distribution-specific fixed versions.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-908: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2021-29623 mapping review

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Vulnerability profileCVE Program record
Severity
Low
CVSS
3.6 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
8Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
3.6CVSS 3.1LowCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N12.5Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

3.6Low
CVSS 3.1 vector shape for CVE-2021-29623Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Exiv2exiv2< v0.27.4Listed
Weakness

CWE details

CWE-908

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-908 · source CWE mapping

Use of Uninitialized Resource

Use of Uninitialized Resource represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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