CyberSecBulletin
CVE-2019-5786Exploited in the wildNVD status: Analyzed

Google Chrome Blink Use-After-Free

Published Updated By the CyberSecBulletin desk

CVE-2019-5786 is a medium-severity use after free vulnerability in Chrome from Google, with a CVSS 3.1 base score of 6.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 72.0.3626.121 as the first without the flaw, so updating Chrome to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on May 23, 2022, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update Chrome to 72.0.3626.121 or a later version.
  2. CISA's required action: Apply updates per vendor instructions.
  3. Read the advisory on chromereleases.googleblog.com for workarounds and exact fixed builds.
  4. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
  5. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
GoogleChromebefore 72.0.3626.12172.0.3626.121

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.16.5MediumNVD
CVSS 3.16.5MediumCISA (ADP)
CVSS 2.04.3MediumNVD

Official description

Object lifetime issue in Blink in Google Chrome prior to 72.0.3626.121 allowed a remote attacker to potentially perform out of bounds memory access via a crafted HTML page.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. Deadline for US federal agencies to remediate, set by CISA.
  4. CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: partial).
  5. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Technical write-ups (may include proof of concept)

Other vulnerabilities in Chrome

All Chrome vulnerabilities

Recent Use After Free vulnerabilities

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