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CVE Record

CVE-2017-7805: During TLS 1.2 exchanges, handshake hashes are generated which point to a message buffer.

During TLS 1.2 exchanges, handshake hashes are generated which point to a message buffer. This saved data is used for later messages but in some cases, the handshake transcript can exceed the space available in the current buffer, causing the allocation of a new buffer. This leaves a pointer pointing to the old, freed buffer, resulting in a use-after-free when handshake hashes are then calculated afterwards. This can result in a potentially exploitable crash. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2017-7805 is a memory-safety flaw in older Mozilla Firefox, Firefox ESR, and Thunderbird during TLS 1.2 handshakes. Under some conditions, the software could use freed memory and crash in a way Mozilla described as potentially exploitable.

Executive priority

Treat as priority cleanup if legacy Mozilla clients exist. For modern managed fleets, the main action is confirming absence of obsolete Firefox and Thunderbird versions rather than emergency response.

Technical view

During TLS 1.2 exchanges, saved handshake hash data could point to an old message buffer after the transcript exceeded the current buffer and reallocation occurred. Later hash calculation could dereference freed memory, causing a use-after-free and potentially exploitable crash.

Likely exposure

Exposure is limited to Firefox before 56, Firefox ESR before 52.4, and Thunderbird before 52.4, including downstream packages from Linux distributions or vendors that shipped those versions.

Exploitation context

The provided sources do not show CISA KEV listing or active exploitation. The vulnerability is remotely relevant to TLS 1.2 handling, but the bundle does not specify exploit prerequisites, attacker position, or public weaponization.

Researcher notes

The source bundle provides a clear root cause and affected version thresholds, but no CVSS vector, CWE, exploit confirmation, or detailed patch mechanics. Avoid assuming impact beyond a potentially exploitable crash.

Mitigation direction

  • Upgrade Firefox to 56 or later where still applicable.
  • Upgrade Firefox ESR to 52.4 or later where still applicable.
  • Upgrade Thunderbird to 52.4 or later where still applicable.
  • Apply vendor package updates from Mozilla, Debian, Red Hat, Gentoo, or Oracle as applicable.
  • Retire unsupported legacy Mozilla client builds from managed endpoints.

Validation and detection

  • Inventory endpoints for installed Firefox, Firefox ESR, and Thunderbird versions.
  • Confirm no Firefox versions below 56 remain in use.
  • Confirm no Firefox ESR or Thunderbird versions below 52.4 remain in use.
  • Check Linux distribution package advisories for backported fixes.
  • Review vulnerability scanner results against the exact installed package versions.
Prepared
Confidence
high
Sources
12

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

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CVE-2017-7805 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
11Source 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.