Weekly breach brief

Data breaches in the week of 1–7 December 2025

20 data breaches on the tracker, 20 confirmed by the organisation or a regulator.

Breaches: 20
Notices in CA and WA: 11
Ransomware claims: 234
Largest: 817,808

The largest

KinoKong 817,808 accounts
Zilvia.net 287,863 accounts

Every breach this week, by country

United States 18

Healthcare Interactive, Inc. 4 December 2025 · 3,056,950 Oregon residents
Veradigm LLC 2 December 2025 · 2,672,036 Oregon residents
Farmers Insurance Exchange, Farmers Group, Inc. (its attorney-in fact), and their subsidiaries and affiliates 3 December 2025 · 178,153 Texas residents
Union Home Mortgage Corp. 3 December 2025 · 24,160 Texas residents
University of Pennsylvania 1 December 2025 · 11,455 Texas residents
Dallas County MHMR dba Metrocare Services 3 December 2025 · 8,599 Texas residents
Anchor Computer (MacKenzie-Childs) 4 December 2025 · 3,275 Washington residents
Inotiv, Inc. 2 December 2025 · 940 Texas residents
Theology of the Body Evangelization Team 2 December 2025 · 778 Texas residents
CoVantage Credit Union 2 December 2025 · 613 Texas residents
Madison Partners LLC 2 December 2025 · 360 Texas residents
Petco Animal Supplies Stores, Inc. (“Petco”) 3 December 2025 · 329 Texas residents
MAG DS Corp., dba MAG Aerospace 5 December 2025 · 316 Texas residents
Bleyl Interests Inc 5 December 2025 · 314 Texas residents
Drury Southwest, Inc. 5 December 2025 · 252 Texas residents
Kayali & CO., P.A. 2 December 2025 · 1 Oregon residents
Housing Authority of the City of Los Angeles 5 December 2025
Boutin Jones 3 December 2025

Country being checked 2

KinoKong 6 December 2025 · 817,808 accounts
Zilvia.net 1 December 2025 · 287,863 accounts

Ransomware claims

Gangs named 234 organisations on their leak sites this week, against 162 the week before. A claim is the gang’s word, not a confirmed breach.

Qilin 55 claims
LockBit 5.0 39 claims
Akira 27 claims
Devman 14 claims
INC Ransom 10 claims
SafePay 9 claims

What regulators did

Reprimand · UK Information Commissioner’s Office · Post Office Limited The decision 2 December 2025

Every week

26 Oct – 1 Nov 2026 67 data breaches so far
19–25 October 2026 80 data breaches
12–18 October 2026 54 data breaches
5–11 October 2026 48 data breaches
28 Sept – 4 Oct 2026 68 data breaches
21–27 September 2026 67 data breaches
14–20 September 2026 71 data breaches
7–13 September 2026 46 data breaches
31 Aug – 6 Sept 2026 61 data breaches
24–30 August 2026 59 data breaches
17–23 August 2026 56 data breaches
10–16 August 2026 67 data breaches
3–9 August 2026 69 data breaches
27 Jul – 2 Aug 2026 60 data breaches
20–26 July 2026 39 data breaches
13–19 July 2026 50 data breaches
6–12 July 2026 49 data breaches
29 Jun – 5 Jul 2026 49 data breaches
22–28 June 2026 56 data breaches
15–21 June 2026 40 data breaches
8–14 June 2026 49 data breaches
1–7 June 2026 57 data breaches
25–31 May 2026 54 data breaches
18–24 May 2026 50 data breaches
11–17 May 2026 61 data breaches
4–10 May 2026 53 data breaches
27 Apr – 3 May 2026 48 data breaches
20–26 April 2026 41 data breaches
13–19 April 2026 51 data breaches
6–12 April 2026 38 data breaches
30 Mar – 5 Apr 2026 44 data breaches
23–29 March 2026 61 data breaches
16–22 March 2026 46 data breaches
9–15 March 2026 51 data breaches
2–8 March 2026 41 data breaches
23 Feb – 1 Mar 2026 50 data breaches
16–22 February 2026 45 data breaches
9–15 February 2026 50 data breaches
2–8 February 2026 46 data breaches
26 Jan – 1 Feb 2026 48 data breaches
19–25 January 2026 24 data breaches
12–18 January 2026 47 data breaches
5–11 January 2026 48 data breaches
29 Dec – 4 Jan 2026 30 data breaches
22–28 December 2025 24 data breaches
15–21 December 2025 26 data breaches
8–14 December 2025 28 data breaches
1–7 December 2025 20 data breaches
24–30 November 2025 12 data breaches
17–23 November 2025 32 data breaches
10–16 November 2025 24 data breaches
3–9 November 2025 24 data breaches
27 Oct – 2 Nov 2025 14 data breaches
20–26 October 2025 11 data breaches
13–19 October 2025 13 data breaches
6–12 October 2025 13 data breaches
29 Sept – 5 Oct 2025 16 data breaches
22–28 September 2025 14 data breaches
15–21 September 2025 18 data breaches
8–14 September 2025 18 data breaches
1–7 September 2025 9 data breaches
25–31 August 2025 18 data breaches
18–24 August 2025 14 data breaches
11–17 August 2025 11 data breaches
4–10 August 2025 11 data breaches
28 Jul – 3 Aug 2025 17 data breaches
21–27 July 2025 16 data breaches
14–20 July 2025 24 data breaches
7–13 July 2025 15 data breaches
30 Jun – 6 Jul 2025 14 data breaches
23–29 June 2025 21 data breaches
16–22 June 2025 9 data breaches
9–15 June 2025 15 data breaches
2–8 June 2025 15 data breaches
26 May – 1 Jun 2025 5 data breaches
19–25 May 2025 19 data breaches
12–18 May 2025 15 data breaches
5–11 May 2025 20 data breaches
28 Apr – 4 May 2025 15 data breaches
21–27 April 2025 15 data breaches
14–20 April 2025 10 data breaches
7–13 April 2025 29 data breaches
31 Mar – 6 Apr 2025 19 data breaches
24–30 March 2025 17 data breaches
17–23 March 2025 19 data breaches
10–16 March 2025 25 data breaches
3–9 March 2025 22 data breaches
24 Feb – 2 Mar 2025 61 data breaches
17–23 February 2025 11 data breaches
10–16 February 2025 14 data breaches
3–9 February 2025 15 data breaches
27 Jan – 2 Feb 2025 20 data breaches
20–26 January 2025 11 data breaches
13–19 January 2025 16 data breaches
6–12 January 2025 17 data breaches
30 Dec – 5 Jan 2025 7 data breaches
23–29 December 2024 9 data breaches
16–22 December 2024 23 data breaches
9–15 December 2024 18 data breaches
2–8 December 2024 12 data breaches
25 Nov – 1 Dec 2024 7 data breaches
18–24 November 2024 14 data breaches
11–17 November 2024 18 data breaches
4–10 November 2024 16 data breaches
28 Oct – 3 Nov 2024 13 data breaches
21–27 October 2024 14 data breaches
14–20 October 2024 13 data breaches
7–13 October 2024 22 data breaches
30 Sept – 6 Oct 2024 16 data breaches
23–29 September 2024 11 data breaches
16–22 September 2024 15 data breaches
9–15 September 2024 12 data breaches
2–8 September 2024 15 data breaches
26 Aug – 1 Sept 2024 22 data breaches
19–25 August 2024 16 data breaches
12–18 August 2024 14 data breaches
5–11 August 2024 17 data breaches
29 Jul – 4 Aug 2024 15 data breaches
22–28 July 2024 15 data breaches
15–21 July 2024 18 data breaches
8–14 July 2024 13 data breaches
1–7 July 2024 10 data breaches
24–30 June 2024 17 data breaches
17–23 June 2024 14 data breaches
10–16 June 2024 16 data breaches
3–9 June 2024 19 data breaches
27 May – 2 Jun 2024 20 data breaches
20–26 May 2024 26 data breaches
13–19 May 2024 12 data breaches
6–12 May 2024 17 data breaches
29 Apr – 5 May 2024 20 data breaches
22–28 April 2024 14 data breaches
15–21 April 2024 19 data breaches
8–14 April 2024 14 data breaches
1–7 April 2024 19 data breaches
25–31 March 2024 24 data breaches
18–24 March 2024 31 data breaches
11–17 March 2024 14 data breaches
4–10 March 2024 14 data breaches
26 Feb – 3 Mar 2024 28 data breaches
19–25 February 2024 15 data breaches
12–18 February 2024 12 data breaches
5–11 February 2024 17 data breaches
29 Jan – 4 Feb 2024 17 data breaches
22–28 January 2024 14 data breaches
15–21 January 2024 11 data breaches
8–14 January 2024 21 data breaches
1–7 January 2024 13 data breaches
25–31 December 2023 12 data breaches
18–24 December 2023 32 data breaches
11–17 December 2023 22 data breaches
4–10 December 2023 25 data breaches
27 Nov – 3 Dec 2023 17 data breaches
20–26 November 2023 19 data breaches
13–19 November 2023 14 data breaches
6–12 November 2023 13 data breaches
30 Oct – 5 Nov 2023 17 data breaches
23–29 October 2023 13 data breaches
16–22 October 2023 15 data breaches
9–15 October 2023 15 data breaches
2–8 October 2023 19 data breaches
25 Sept – 1 Oct 2023 9 data breaches
18–24 September 2023 21 data breaches
11–17 September 2023 14 data breaches
4–10 September 2023 14 data breaches
28 Aug – 3 Sept 2023 27 data breaches
21–27 August 2023 23 data breaches
14–20 August 2023 17 data breaches
7–13 August 2023 24 data breaches
31 Jul – 6 Aug 2023 20 data breaches
24–30 July 2023 38 data breaches
17–23 July 2023 25 data breaches
10–16 July 2023 22 data breaches
3–9 July 2023 10 data breaches
26 Jun – 2 Jul 2023 23 data breaches
19–25 June 2023 11 data breaches
12–18 June 2023 16 data breaches
5–11 June 2023 11 data breaches
29 May – 4 Jun 2023 9 data breaches
22–28 May 2023 18 data breaches
15–21 May 2023 15 data breaches
8–14 May 2023 14 data breaches
1–7 May 2023 9 data breaches
24–30 April 2023 17 data breaches
17–23 April 2023 11 data breaches
10–16 April 2023 17 data breaches
3–9 April 2023 12 data breaches
27 Mar – 2 Apr 2023 18 data breaches
20–26 March 2023 13 data breaches
13–19 March 2023 14 data breaches
6–12 March 2023 17 data breaches
27 Feb – 5 Mar 2023 21 data breaches
20–26 February 2023 7 data breaches
13–19 February 2023 15 data breaches
6–12 February 2023 9 data breaches
30 Jan – 5 Feb 2023 15 data breaches
23–29 January 2023 12 data breaches
16–22 January 2023 14 data breaches
9–15 January 2023 10 data breaches
2–8 January 2023 8 data breaches
26 Dec – 1 Jan 2023 2 data breaches

Follow the brief: one entry a week (Atom). The 2026 report has the year so far.

From the data breach tracker: official notices, breach databases and the news, every fact with its source. Open data (CC BY 4.0) · How the tracker works · Official registers · Corrections and changes · Found a mistake? Tell us and we correct it.