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CVE Record

CVE-2017-7758: An out-of-bounds read vulnerability with the Opus encoder when the number of channels in an audio stream ch...

An out-of-bounds read vulnerability with the Opus encoder when the number of channels in an audio stream changes while the encoder is in use. This vulnerability affects Firefox < 54, Firefox ESR < 52.2, and Thunderbird < 52.2.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2017-7758 is an old Mozilla client vulnerability in the Opus audio encoder. It could read outside intended memory when audio channel counts changed during encoder use. It affected Firefox before 54, Firefox ESR before 52.2, and Thunderbird before 52.2. The bundle does not provide a CVSS score or confirmed business impact.

Executive priority

Treat this as a legacy software hygiene issue unless vulnerable Mozilla clients are still present. The main urgency is finding and removing old browser or mail-client versions that may remain in unmanaged endpoints, archived images, or long-lived enterprise systems.

Technical view

The flaw is an out-of-bounds read in Mozilla's Opus encoder during active encoding when an audio stream changes channel count. Affected products are Firefox < 54, Firefox ESR < 52.2, and Thunderbird < 52.2. No CWE, CVSS vector, exploit trigger details, or patch internals are provided in the bundle.

Likely exposure

Exposure is mainly legacy Mozilla installations or enterprise images still running Firefox below 54, Firefox ESR below 52.2, or Thunderbird below 52.2. Current supported Mozilla versions should not be affected based on the fixed-version thresholds.

Exploitation context

The source bundle marks KEV as false and provides no cited evidence of active exploitation. It also does not describe exploit prerequisites beyond the vulnerable audio encoder condition, so exploitability and real-world abuse should be treated as unconfirmed from these sources.

Researcher notes

Evidence is limited: no CVSS, CWE, exploit status, or detailed impact statement is included. Research should focus on confirming affected code paths from Mozilla Bugzilla and advisories, then validating whether any deployed clients still meet the vulnerable version criteria.

Mitigation direction

  • Upgrade Firefox to 54 or later, preferably a supported current release.
  • Upgrade Firefox ESR to 52.2 or later, preferably a supported ESR release.
  • Upgrade Thunderbird to 52.2 or later, preferably a supported current release.
  • Apply relevant Debian or Red Hat security updates where Mozilla packages are distro-managed.
  • Check Mozilla and OS vendor advisories for any environment-specific guidance.

Validation and detection

  • Inventory installed Firefox, Firefox ESR, and Thunderbird versions across managed endpoints.
  • Flag any Firefox versions below 54 for remediation.
  • Flag any Firefox ESR or Thunderbird versions below 52.2 for remediation.
  • Confirm distro package versions against Debian and Red Hat advisories where applicable.
  • Verify vulnerable versions are absent from gold images and legacy application stacks.
Prepared
Confidence
medium
Sources
10

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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CVE-2017-7758 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
9Source 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
MozillaFirefoxunspecifiedListed
MozillaFirefox ESRunspecifiedListed
MozillaThunderbirdunspecifiedListed
Weakness

CWE details

No CWE listed

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