CVE-2017-17821
WTF/wtf/FastBitVector.h in WebKit, as distributed in Safari Technology Preview Release 46, allows remote attackers to cause a denial of service (buffer overflow) or possibly have unspecified other impact because it calls the…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.38%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
WTF/wtf/FastBitVector.h in WebKit, as distributed in Safari Technology Preview Release 46, allows remote attackers to cause a denial of service (buffer overflow) or possibly have unspecified other impact because it calls the FastBitVectorWordOwner::resizeSlow function (in WTF/wtf/FastBitVector.cpp) for a purpose other than initializing a bitvector size, and resizeSlow mishandles cases where the old array length is greater than the new array length.
- CVSS 3.0
- 9.8 CRITICALCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 1.38% probability · 72th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-119
- Affected
- apple/safari
- Source
- cve@mitre.org
EPSS 1.4% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugs.webkit.org/show_bug.cgi?id=181020Permissions Required
- https://github.com/dwfault/PoCs/blob/master/WebKit%20Misuse%20of%20WTF:wtf:FastBitVector%20result%20in%20potential%20BOF/WebKit%20Misuse%20of%20WTF:wtf:FastBitVector%20result%20in%20potential%20BOF.mdThird Party Advisory
- https://bugs.webkit.org/show_bug.cgi?id=181020Permissions Required
- https://github.com/dwfault/PoCs/blob/master/WebKit%20Misuse%20of%20WTF:wtf:FastBitVector%20result%20in%20potential%20BOF/WebKit%20Misuse%20of%20WTF:wtf:FastBitVector%20result%20in%20potential%20BOF.mdThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.