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CVE Record

CVE-2017-5448: An out-of-bounds write in "ClearKeyDecryptor" while decrypting some Clearkey-encrypted media content.

An out-of-bounds write in "ClearKeyDecryptor" while decrypting some Clearkey-encrypted media content. The "ClearKeyDecryptor" code runs within the Gecko Media Plugin (GMP) sandbox. If a second mechanism is found to escape the sandbox, this vulnerability allows for the writing of arbitrary data within memory, resulting in a potentially exploitable crash. This vulnerability affects Firefox ESR < 45.9, Firefox ESR < 52.1, and Firefox < 53.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2017-5448 is an old Firefox memory-safety flaw in media decryption. Affected browsers could crash, and the issue might become more serious if combined with a separate sandbox escape. The sources do not show known active exploitation, and CISA KEV is false.

Executive priority

Treat this as a legacy-browser remediation item. It is not KEV-listed in the supplied data, but vulnerable Firefox builds are far out of support and should be removed or updated as part of endpoint hygiene.

Technical view

The vulnerability is an out-of-bounds write in Mozilla's ClearKeyDecryptor while handling some ClearKey-encrypted media. The vulnerable code runs inside the Gecko Media Plugin sandbox. Sources say arbitrary memory writes and a potentially exploitable crash are possible only if another mechanism escapes that sandbox.

Likely exposure

Exposure is mainly organizations still running Firefox before 53 or Firefox ESR before 45.9 or 52.1, including legacy Linux packages covered by Debian and Red Hat advisories. Modern, maintained Firefox installations should not be affected based on the version bounds provided.

Exploitation context

The public bundle describes exploitation as conditional on processing certain ClearKey-encrypted media and also needing a sandbox escape for broader impact. No provided source claims active exploitation, public weaponization, or KEV listing.

Researcher notes

Key constraints are the GMP sandbox boundary and absence of supplied exploit evidence. Validation should focus on version exposure and vendor patch state, not speculative exploit chains. The provided bundle has no CVSS, CWE, or detailed root-cause patch notes.

Mitigation direction

  • Upgrade Firefox to version 53 or later.
  • Upgrade Firefox ESR to 45.9, 52.1, or later.
  • Apply Mozilla, Debian, or Red Hat security updates where applicable.
  • Retire or isolate systems that cannot run supported Firefox builds.
  • Check vendor advisories for any environment-specific guidance.

Validation and detection

  • Inventory Firefox and Firefox ESR versions across endpoints and images.
  • Flag Firefox below 53 and ESR below 45.9 or 52.1.
  • Confirm Linux package updates match Debian or Red Hat advisory coverage.
  • Review browser crash telemetry for legacy Firefox media-processing crashes.
  • Verify unsupported browsers are removed from managed builds.
Prepared
Confidence
high
Sources
9

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

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ATT&CK lookup starting points

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CVE-2017-5448 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

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

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
MozillaFirefox ESRunspecified, unspecifiedListed
MozillaFirefoxunspecifiedListed
Weakness

CWE details

No CWE listed

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