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CVE-2026-26740: Buffer Overflow vulnerability in giflib v.5.2.2 allows a remote attacker to cause a denial of service via t...

Buffer Overflow vulnerability in giflib v.5.2.2 allows a remote attacker to cause a denial of service via the EGifGCBToExtension overwriting an existing Graphic Control Extension block without validating its allocated size.

HighCVSS 8.2Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A remotely supplied GIF processed by giflib 5.2.2 may overwrite memory and crash the affected process or service. No authentication or user interaction is indicated. The documented primary impact is denial of service; the supplied evidence does not establish code execution.

Executive priority

Prioritize remediation for internet-facing or automated image-processing services because exploitation requires no privileges or interaction and can cause substantial outages. Address internal systems according to whether they accept untrusted GIF files. Do not defer solely because active exploitation is unconfirmed.

Technical view

EGifGCBToExtension can overwrite an existing Graphic Control Extension block without confirming that its allocation is large enough, causing an out-of-bounds memory write. CVSS 3.1 rates it 8.2: network-accessible, low complexity, unauthenticated, and capable of high availability impact with limited integrity impact.

Likely exposure

Exposure is most likely where giflib 5.2.2 processes attacker-controlled or otherwise untrusted GIF data, particularly in automated, network-facing image services. The supplied affected-product metadata is incomplete, so bundled and transitive copies must be investigated rather than relying solely on product names.

Exploitation context

A public technical disclosure is referenced, increasing reproducibility risk. However, the CVE is not identified as KEV, and the supplied sources provide no evidence of active exploitation. Treat claims beyond denial of service cautiously unless vendor evidence emerges.

Researcher notes

CWE-787 and the description support an out-of-bounds write in EGifGCBToExtension. The declared outcome is denial of service, while the CVSS vector also records limited integrity impact. Product mapping and corrected-version details are incomplete in the supplied bundle; verify applicability through vendor VEX and advisories.

Mitigation direction

  • Inventory direct, bundled, and transitive deployments of giflib 5.2.2.
  • Apply applicable vendor updates identified by Red Hat or other product suppliers.
  • Consult vendor guidance for corrected versions because the supplied bundle does not name one.
  • Temporarily restrict untrusted GIF processing where updates cannot be applied promptly.
  • Isolate image-processing workloads to limit disruption from process crashes.

Validation and detection

  • Confirm deployed and embedded giflib versions through package inventories and software bills of materials.
  • Compare each Red Hat deployment against its CVE page, VEX data, and applicable advisories.
  • Verify updated packages originate from supported vendor repositories and cover the affected component.
  • Test normal GIF-processing workflows after remediation without using public exploit material.
  • Monitor image-processing services for unusual crashes or repeated malformed-input failures.
Prepared
Confidence
medium
Sources
8

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-787: 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-2026-26740 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.2 (3.1)
Known Exploited
No
Published

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

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.

2CVSS vectors
5Timeline events
2ADP providers
22Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: yesTechnical Impact: partial

CVSS vector scores

2 official scores

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
8.2CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H3.94.2CISA-ADP
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

8.2High
CVSS 3.1 vector shape for CVE-2026-26740Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
redhat-SADPgiflib: giflib: Denial of Service via buffer overflow in EGifGCBToExtension
other:Red Hat severity ratingcvssV3_1
  • 2026-03-18T19:01:41.415Z: Reported to Red Hat.
  • 2026-03-18T00:00:00.000Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

CWE-787

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

CWE-787 · source CWE mapping

Out-of-bounds Write

Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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