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Fencer Vulns
high 8.8

CVE-2019-18800 json

Viber through 11.7.0.5 allows a remote attacker who can capture a victim's internet traffic to steal their Viber account, because not all V…

published 2019-11-06 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-8505

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

Viber through 11.7.0.5 allows a remote attacker who can capture a victim's internet traffic to steal their Viber account, because not all Viber protocol traffic is encrypted. TCP data packet 9 on port 4244 from the victim's device contains cleartext information such as the device model and OS version, IMSI, and 20 bytes of udid in a binary format, which is located at offset 0x14 of this packet. Then, the attacker installs Viber on his device, initiates the registration process for any phone number, but doesn't enter a pin from SMS. Instead, he closes Viber. Next, the attacker rewrites his udid with the victim's udid, modifying the viber_udid file, which is located in the Viber preferences folder. (The udid is stored in a hexadecimal format.) Finally, the attacker starts Viber again and enters the pin from SMS.

Exploit prediction

1.66% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • thesamarkand.tumblr.com https://thesamarkand.tumblr.com/post/188785277609/viber-messenger-remote-account-reset-0day referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-311 Missing Encryption of Sensitive Data
  • CWE-319 Cleartext Transmission of Sensitive Information

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.